BelowTheLine on FB has some chats for reserve questions, no dedicated DFP trade chats that I know of. I’m new here but I haven’t heard of people trading DFPs around, either from my class or people in my crashpad.

Probably obvious, but you should start by getting smart on PBS to maximize your chances of desired days off/work block length. If you don’t know the criteria that will make PBS autofail a layer, or what the 2 reserve waivers do/when to select them, there’s a great (dense) PBS user guide on comply.