Poncho vs. "regular" rain gear --- personal preference. I found two issues against a poncho on the AT last year. One likely won't be a problem for you, but I started the trail (from Georgia) quite early, so apart from snow there were lots of blowdowns in the first month or so, always an issue when your raingear is also your only shelter (well, apart from the AT shelters). The other was that as the seasons progressed, I found along the AT there were a lot of times when it was too warm to want to wear raingear (even when raining), but nice to have the pack covered. Out west I've not used a pack cover much, but it was a nice thing to have for a good part of the AT.

All that said, I'm a big fan of ponchos in general.

Hanging food along the AT: yes, if you sleep in or near shelters, to keep it away from rodents. I used an Ursack Minor, an explicitly rodent-proof food bag, and did well with that just sleeping with my food, but otherwise I would have hung it in the shelters every night like most folks do.