ANSWER TO Question 1 Above
1A: "Dr. Skinny" does not sound the same as "DR. SKINNY RAPID WEIGHT LOSS SPA" - they do have that one part "Dr Skinny" is identical but the overall impression is different - although "Dr. Skinny" is a dominate feature of their mark - perhaps. Such does give them a point to argue but in the end I submit you would prevail on such "test".
1B: You have a very different logo - that is VERY good. You would want to stay away from any LOGO that looks like theirs.
1C: You sell on Amazon then you sell in North Carolina. And while the location of the SPA may be in North Carolina, I suspect they advertise their services on the internet and anyone can travel to NC and use the spa. Location does not help you.
1D: We both do have Facebook pages that promote weight management and dietary messages. Good point to consider. Again, this issue is about RISK tolerance. What level of risk can you tolerate. The more you actions start approaching the selling of a weight loss service they provide, the more likely you are to be sued (and perhaps lose). The more you change your logo to look like theirs the more likely you would be sued (and perhaps lose.
First Extreme: You simply do what you are doing - just sell pills under the name "Dr. Skinny" over the internet.
Second Extreme: Suppose you setup a SPA right next door to theirs, Had a Big Sign that said "Dr. Skinny" in big letters and then below another sign that said "Weight Loss Spa" . . . you are going to get sued.
The more your actions move from Extreme 1 to Extreme 2 the higher the risk of being sued. Try to stay toward extreme 1.
Just giving "Weight Loss Tips" is not a big deal but it does nudge you in the direction to Extreme 2 slightly.
At this point I submit it is unlikely that contacting them will lead to anything good for you happening in the long run.
That said, lets say you do not contact them and they sue. The will, after the fact, say if you would have just asked they would have not had a problem. I do know anyone involved I just know people from past experience - they always say that and it is never true.
If you are going to be investing lots of money in a brand name you want it to be a strong brand name. "Strong" means the mark had little meaning for your goods before you started using the mark and advertising the mark with your products.
Example: "Apple" for computers. No one would have associated Apple with computers before Apple started using the mark.
Now "Apple" for apples is not only weak, it is generic and not registerable as a mark.
Apple for computers is arbitrary but Apple for apples is generic. You typically want your brand name to be toward the "arbitrary" side.
Now "Dr. Skinny" for weight loss pills is a clever Brand name - which means such is probably used already. When I do a google search for "Dr. Skinny" is get 9,000 hits. There is a "Skinny's" registered mark for weight loss services. Thus, your biggest problem may not be the trademark owner you identified. Need to do your homework here - may be people with "common law" rights.
Below I will give you some examples of where similar marks have been OK and not OK
EXAMPLES WHERE ADDING “STUFF” TO A MARK DOES NOT AVOID Likelihood of confusion
Likelihood of confusion is not necessarily avoided between otherwise confusingly similar marks merely by adding or deleting a house mark, other distinctive matter, or a term that is descriptive or suggestive of the named goods or services; if the dominant portion of both marks is the same, then the marks may be confusingly similar notwithstanding peripheral differences.
ML v ML ***** *****S
See, e.g., In re Mighty Leaf Tea, 601 F.3d 1342, 1347-48, 94 USPQ2d 1257, 1260-61 (Fed. Cir. 2010) (affirming TTAB’s finding that applicant’s mark, ML, is likely to be perceived as a shortened version of registrant's mark, ML ***** *****S (stylized), when used on the same or closely related skin-care products);
VEUVE ROYALE v VEUVE CLICQUOT
Palm Bay Imps., Inc. v. Veuve Clicquot Ponsardin Maison Fondee En 1772, 396 F.3d 1369, 1372-73, 73 USPQ2d 1689, 1692 (Fed. Cir. 2005) (affirming TTAB’s holding that contemporaneous use of appellant’s mark, VEUVE ROYALE, for sparkling wine, and appellee’s marks, VEUVE CLICQUOT and VEUVE CLICQUOT PONSARDIN, for champagne, is likely to cause confusion, noting that the presence of the “strong distinctive term [VEUVE] as the first word in both parties’ marks renders the marks similar, especially in light of the largely laudatory (and hence non-source identifying) significance of the word ROYALE”);
GASPAR’s ALE v JOSE GASPAR GOLD
In re Chatam Int’l Inc., 380 F.3d 1340, 1343, 71 USPQ2d 1944, 1946 (Fed. Cir. 2004) (“Viewed in their entireties with non-dominant features appropriately discounted, the marks [GASPAR’S ALE for beer and ale and JOSE GASPAR GOLD for tequila] become nearly identical.”); Hewlett-Packard Co. v. Packard Press, Inc., 281 F.3d 1261, 1266, 62 USPQ2d 1001, 1004 (Fed. Cir. 2002) (finding that, even though applicant’s mark PACKARD TECHNOLOGIES (with “TECHNOLOGIES” disclaimed) does not incorporate every feature of opposer’s HEWLETT PACKARD marks, a similar overall commercial impression is created);
MAX v MAX (with pillar design)
In re Max Capital Grp. Ltd., 93 USPQ2d 1243, 1248 (TTAB 2010) (holding applicant's mark, MAX with pillar design, and registrant’s mark, MAX, likely to cause confusion, noting that the “addition of a column design to the cited mark . . . is not sufficient to convey that [the] marks . . . identify different sources for legally identical insurance services”);
VANTAGE TITAN v TITAN
In re Toshiba Med. Sys. Corp., 91 USPQ2d 1266, 1271 (TTAB 2009) (holding VANTAGE TITAN for MRI diagnostic apparatus, and TITAN for medical ultrasound device, likely to cause confusion, noting that the marks are more similar than they are different and that the addition of applicant’s “product mark,” VANTAGE, to the registered mark would not avoid confusion);
SAM EDELMAN v EDELMAN
In re SL&E Training Stable, Inc., 88 USPQ2d 1216, 1219 (TTAB 2008) (holding SAM EDELMAN and EDELMAN, both for wallets and various types of bags, likely to cause confusion, noting that there are strong similarities between the marks because they share the same surname, and that consumers viewing the mark EDELMAN may perceive it as an abbreviated form of SAM EDELMAN because it is the practice in the fashion industry to refer to surnames alone);
CORAZON BY CHICA v CORAZON (with design)
In re Chica, Inc., 84 USPQ2d 1845, 1848-49 (TTAB 2007) (holding CORAZON BY CHICA with design, and CORAZON with design, both for jewelry, likely to cause confusion, noting that, “to many consumers, applicant’s mark for the identical word ‘Corazon’ followed by the phrase ‘BY CHICA’ will simply be viewed as the identification of the previously anonymous source of the goods sold under the mark CORAZON”);
MACHO COMBOS v MACHO (stylized)
In re El Torito Rests. Inc., 9 USPQ2d 2002 (TTAB 1988) (holding MACHO COMBOS (with “COMBOS” disclaimed), and MACHO (stylized), both for food items as a part of restaurant services, likely to cause confusion); In re Computer Sys. Ctr. Inc., 5 USPQ2d 1378, 1381 (TTAB 1987) (holding CSC ADVANCED BUSINESS SYSTEMS for retail computer store services and computer maintenance and repair services in connection therwith, and CSC for various computer-related services, likely to cause confusion, noting that “the inclusion of ‘ADVANCED BUSINESS SYSTEMS’ as a feature of applicant’s mark is not likely to help customers . . . distinguish the source of each party’s service”);
RESPONSE v RESPONSE CARD
In re Equitable Bancorporation, 229 USPQ 709, 711 (TTAB 1986) (holding RESPONSE and RESPONSE CARD (with “CARD” disclaimed), both for banking services, likely to cause confusion, noting that “the addition of descriptive matter to one of two otherwise similar, nondescriptive marks will not serve to avoid a likelihood of confusion”);
EXAMPLES WHERE ADDING “STUFF” TO A MARK DOES AVOID Likelihood of confusion
Additions or deletions to marks may be sufficient to avoid a likelihood of confusion if:
(1) the marks in their entireties convey significantly different commercial impressions; or
(2) the matter common to the marks is not likely to be perceived by purchasers as distinguishing source because it is merely descriptive or diluted. See, e.g.,
CAPITAL CITY BANK v CITIBANK
Citigroup Inc. v. Capital City Bank Group, Inc., 637 F.3d 1344, 1356, 98 USPQ2d 1253, 1261 (Fed. Cir. 2011) (affirming TTAB’s holding that contemporaneous use of applicant’s CAPITAL CITY BANK marks for banking and financial services, and opposer’s CITIBANK marks for banking and financial services, is not likely cause confusion, based, in part, on findings that the phrase “City Bank” is frequently used in the banking industry and that ”CAPITAL” is the dominant element of applicant’s marks, which gives the marks a geographic connotation as well as a look and sound distinct from opposer’s marks);
THE RITZ KIDS v RITZ
Shen Mfg. Co. v. Ritz Hotel Ltd., 393 F.3d 1238, 1245, 73 USPQ2d 1350, 1356-57 (Fed. Cir. 2004) (reversing TTAB’s holding that contemporaneous use of THE RITZ KIDS for clothing items (including gloves) and RITZ for various kitchen textiles (including barbeque mitts) is not likely to cause confusion, because, inter alia, THE RITZ KIDS creates a different commercial impression);
DEER-B-GON v DEER AWAY
Safer, Inc. v. OMS Invs., Inc., 94 USPQ2d 1031, 1044-45 (TTAB 2010) (holding DEER-B-GON for animal repellant used to repel deer, other ruminant animals, and rabbits, and DEER AWAY and DEER AWAY PROFESSIONAL for repellant for repelling deer, other big game, and rabbits, not likely to cause confusion, noting that “DEER” is descriptive as applied to the relevant goods and thus has no source-indicating significance);
CATFISH BOBBERS v CTFISH
In re Farm Fresh Catfish Co., 231 USPQ 495, 495-96 (TTAB 1986) (holding CATFISH BOBBERS (with “CATFISH” disclaimed) for fish, and BOBBER for restaurant services, not likely to cause confusion, because the word “BOBBER” has different connotation when used in connection with the respective goods and services);
GOLDEN CRUST v GOLD’N CRUST
In re Shawnee Milling Co., 225 USPQ 747, 749 (TTAB 1985) (holding GOLDEN CRUST for flour, and ADOLPH’S GOLD’N CRUST and design (with “GOLD’N CRUST” disclaimed) for coating and seasoning for food items, not likely to cause confusion, noting that, because “GOLDEN CRUST” and “GOLD’N CRUST” are highly suggestive as applied to the respective goods, the addition of “ADOLPH’S” is sufficient to distinguish the marks);