They might get Star Wars too, the Lego Dimensions and Disney Infinity figurines are different enough that I don't think they will compete with one another.
I don't think Disney will allow it.
Star Wars Disney Infinity is going to be a huge thing basically on its own and will be the trump card of Disney Infinity 3 with The Force Awakens releasing this holiday.
Still there are plenty of IP for LEGO to get. Jurassic Park, Harry Potter, Ghostbusters, Simpsons (!), more DC characters, etc.