I cannot talk fm experience but I can tell what I was told when I interviewed with AT.

1. Expect ATL first but there is a chance of MKE and a slight shot MCO. Either A/C can be assigned but 737s go first in each class.
2. No clue!
3. We were told to expect 3-4 years on reserve.
4. Reserves are used a lot.

Not a complete answer but it might help.

C9