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I just wanted to get a little more information about little Emily to better assist you. How often and how much are you feeding her the formula? Also, if you aren't already you could try using a warm wash cloth to help stimulate her to defecate. Since Emily most likely wasn't getting the nutrition she needed prior to Monday, it is possible that the food hasn't had a chance to move through her system yet but if she still is not defecating for you (usually about 1-2hrs after a meal) then I would have her checked out in person by a veterinarian.
The wash cloth should just be luke warm. It sounds like she is doing pretty well for you otherwise, which is great to hear! Were her stools formed or diarrhea yesterday?
From what I can tell, it sounds like you are doing everything right for her. I recommend that you try to make an appointment with a general practice vet to get her first check up just to be sure she is on the right track since she is so little but I wouldn't worry too much about the defecation at this time. If there is still no signs of defecation by tomorrow afternoon, I would defiantly have her seen at that point to be sure things are moving along normally and also to check for and treat any intestinal parasites she may have.
Absolutely! Good luck with your sweet little kitten!