Talking of the Windows Store pre-order page, I noticed there is a link at the bottom of the page that says Forza Horizon 3 support:
Obviously most of it is stuff we already know but there are a few bits of information about how we expand our festival and gain fans. It says we have to build our own festival hubs, choosing from 4 locations. There’s also some things about convoys in the ANNA section but I’m not sure if this is new or whether this was in Horizon 1/2.