Sorry to hear about your disease bothering you.
I've been on Remicade for 10.5 years and I was also terrified of starting it -- but hair loss was the last thing I was worried about. I've also never heard of anyone losing hair on Remicade. (Steroids like prednisone, though, they can cause all sorts of weird hair loss/growth symptoms. . .) Poor nutrition can also cause hair loss, breakage, dryness, etc., so it may be that whatever medication(s) work for you could improve your hair if they help you to improve your nutritional status. (I hope that's something to look forward to!)
Your doctor wants to put you on Imuran *and* Remicade at the same time? It's not the weirdest thing in the world, but you may be able to try one at a time. That way, if you get side effects, at least you'll know which drug is causing them!
Anyway, Remicade and Humira work in basically the same way -- they're different giant molecules with the same active site (the lock/key mechanism that allows them to attach to TNF-alpha and signal your immune system to destroy it) -- so the range of possible side effects with Remicade is similar to what's possible with Humira. I hope you tolerate Remicade better, if that's what's prescribed for you.
Good luck!