1. How often do you have to empty?
I usually empty about 4 - 6 times a day. Once first thing in the morning, then just before lunch, then just before I leave work to go home then about 2 - 3 times before bed. As Summerstorm said, it's usually only when I pee anyway, no extra trips really.
2. Can you sleep through the night?
I usually have to get up to pee so empty then, but if I didn't have to get up to pee, I could usually go through the night. I say 'usually' cos there are times when I should have gotten up to empty but slept through and have woken up in a mess - but those times are rare.
3. Do you feel more comfortable with the ostomy support/belt? Can you wear this even when you sleep?
I've never worn a belt.
4. How long did it take before you could get back to work [assuming it is desk work]?
Most people tend to be able to get back to work after about 6 - 8 weeks. I was a kid when I had my surgery and was back in the pool swimming a month after my surgery (but, as you probably know, kids are way more resiliant than adults).
Good luck with your decision.