Hi - I recently had my transfer case replaced due to the worsening of these problems. I don't have the paperwork in front of me at the moment, but I will get you a copy if you PM me. So I can answer question #1 and say that it absolutely sounds like a transfer case problem.

If I remember correctly, my actuator failed in the manner that you mentioned and my warranty company replaced the entire thing, rather than rebuild. I'll get the part number for the transfer case in a bit. Also, you may have luck finding a rebuilt part, if you're willing to do that route.

I'll get back to you!