Hey, everyone. Word of advice here. Don't get mad in advance!! You have no idea what's going to happen the day you go. Be prepared. Follow this thread. That's all you can do. RotR is a very complex bunch of stuff (that's the technical, nonspoiler term!) and it's still not working 100% of the time. In fact, I don't think there's any ride at WDW that runs 100% of the time.
You can have a FP+ for whatever and that ride may not be working when you get there and that was the only time you had to ride it. Even if they give you an anytime FP+ as compensation, it doesn't matter, because your chance to ride whatever it was is gone. This happens. It stinks, but it happens.
Want to ride the railroad? Too bad. It's closed until Tron construction is finished. I'm not amused by this at all, but I can't make them change things.
Approach this whole RotR BG situation with the attitude that you
will get a BG. OK, so maybe you won't. Maybe something will happen and the ride will be down all day and no one will ride or your app won't work or you'll be the first backup BG that doesn't get to ride. But don't start thinking negative stuff now. It's not helpful. To you.
I have spoken.