Andrew,
Sorry to hear you have to get surgery for your bilateral cubital tunnel. I go to a major University Medical center in Chicago and they are fairly progressive with their treatment. They do not offer the Epicondylectomy, and I never read much that thrilled me about this surgery. My MD suggested the submuscular for me because I didn't have a lot of "padding", and I'm a average sized girl. I did get a second opinion from another MD who suggested subQ, so I almost feel that the surgeon suggests whatever they're more experienced at

But don't let that sway you- get the surgery you want!
I agree, there is not a very concise source of info that explains the differences between the surgeries and which one to get. That's because there is currently no "right" answer. Doctors don't really have strong predictors for who responds to which surgery. My MD said there was a 50/50 chance that the release would help. Obviously it didn't. My PA said that a lot of patients were showing short term relief from release and then relapsing. But I have yet to hear/read about someone who was "cured" by the release...and please correct me if I'm wrong. There may be someone on this forum who has.
To answer your other questions:
1) I didn't need a drain either time, but it was a potential both times
2) I had dissolvable stitches
3) I had a nerve block which numbed my entire arm so I actually felt nothing when I woke up (which is awesome). The pain in the first three days is the worst so keep it iced and elevated as much as possible. Pain is about a 5-7/10, but can be managed with drugs and ice. Make a soft fist every so often so your hand doesnt swell too much.
4) I took Norco which took away the pain but makes me feel sick like I was hungover..headache, nauseous. Second time I tried Nucynta- a new drug. It doesnt work as well on pain, but it doesnt make me sick. If your drug doesnt work, ask for another.
5) I have a partial cast which is wrapped in an ace bandage, so its unremovable.
6) I had to wait 3 months between surgeries.
Good luck to you. I too was very nervous about surgery...all three times

That's expected when they are rewiring your arm! I hope you can find some time to relax before your surgeries. It does sucks to have to go through this but it is worth it to get your arms back to full use. Please don't hesitate to ask me any more questions you may come up with.
Jill