What all will fit?

I doubt the accessories will be much of an issue. The V6 should have all the mounts, can't see why things like the alt and PS wouldn't hook up fine.

The issue I see is with the transmission. Almost certain you have a 45RFE, which probably won't be spelled out on the window sticker. I don't know that a 5.7 would be easier but it has a better chance of the Hemi PCM talking to the TCM and working. The 5.9 PCM will not talk to the TCM and will never work.

I think your idea of doing a 5.9 swap since it was available in the Durango is great. Just as long as you swap the transmission at the same time. The issue is the 45RFE and mating it to a 5.9 and making it shift.