The process you describe is an involved one and several different areas of law are likely to affect your process. First, a business to make loans to consumers must be licensed by a state or a federal agency in order to be able to offer loans to consumers and must then follow the regulatory requirements of the state or federal agency that grants the authority to lend. If a lender elects to be state licensed then, in order to conduct business in any state the lender must obtain individual licensing in each state (which normally requires completing an application for approval with the state's banking or finance department, which normally requires the lender to have an office in the state and to have substantial assets to support the business) similar requirements also need to be met to obtain federal licensing (but, if that can be obtained, then authority from each individual state is normally not required).
If sales of a loan are to be sold as an investment, then again, state licensing may be required as this may qualify as an "investment" which state agencies (or the SEC in case of a national sale) also regulate (normally called investment divisions, but sometimes are also part of the state banking agencies).
Third, as consumer loans secured by real estate are what you discuss, this often also requires a full understanding of state laws (even if one is nationally licensed to lend) to assure usury, consumer rights (dower, common law, discrimination, judgment, etc.) are full complied with.
It is not easy to specify what type of lawyer you may need, as this area covers business law, banking law, consumer protection law, and investment law. You may want to search for an attorney who practices in all of these areas or who has experience in all of these areas. Further, as you also indicate you will be using an online firm you also should be well versed on the laws of operating the internet, how to form binding agreements online, and other issues specific to the Internet.