I'm just concerned that when we get the new tickets that all the FastPass attractions will already be booked if we have to wait to reserve them until we get there.
currently Shades of Green guests aren't eligible for the FP+ tests. The testers are only at disney owned resorts, and only a few of those at that. If FP+ is still in testing during your trip (which, since I assume your trip is before sept 28th since you already have tickets, it will likely be), then only a fraction of WDW guests will have access to FP+. Regular FP will still be in effect for everyone else.
Maybe I'm not understanding everything correctly. From what I'm reading we will get the new tickets at the gate, does that mean we will still be able to use the old FastPass paper tickets or will we use the new bands? So confusing!
In Sept you will likely get an RFID enabled card when you activate your tickets, not a magicband. Those cards can, from what I've read, be used with the FP machines.
No one knows what Disney is going to do wrt magicbands and shades of green guests. SOG guests have never gotten keys to the world cards, but Fastpass+ is supposed to be based on your tickets, not your accommodations, so I assume Sog guests will eventually get bands of some kind (whether we can personalize ahead of time, who knows).
If you have questions/concerns about how FP+ will integrate with military tickets, I highly encourage you to write to Disney and ask them/let them know. I, too, am concerned about how the 60 day window will work for FP+ and military tickets - esp. since the new salute tickets don't go on sale til August 12, which is less than 60 days before my trip starts. if they're wanting this rolled out by the food and wine festival, it could impact my trip, and I wish they'd give me the info I need already!