Probably all ER, from what I know. Maybe even the next class in Jan.
You will not be able to bid back to ATL until the next AE, which should be in the beginning of March (I think). Junior ATL ER pilot is 71xx. Don't know exactly. So its possible. Likely??? Dunno. This AE had a great deal of movement because of the establishment of new categories. May not be the case on subsequent AE's. The nice part about the NYC ER, however, is that you can bid for atl767 as well as atl7er without having to go through training again and without a seatlock.
I'll be converted to ATL ER's following the latest AE. Personally, I plan on being on reserve until I can hold Capt. Its a senior seat, period. NYC ER is far more junior at the tail end of the list, for your class if you stay there, maybe a year to be a junior line holder/ maybe six months. They should be putting more newhires on that seat now that the AE came up so short...so that could work out for you.
If anything, it would be better for all of you in the Dec 3rd class if there was some variety of airframes available, but I don't think that will be the case.
Long and short of it is that there isn't a bad seat for newhires right now. Anyone who tells you differently is selling you something. We plan on hiring solid numbers next year and you no longer have to fly sideways as a newhire...life is good. Until oil starts kicking our collective ass. Hopefully, this time around the entire industry is smart enough to simply pass the costs on directly to the consumer.
Have fun in indoc.