that's a good question, seeing as the CM costuming for the Black Spire village is pretty much "SW everyday clothing" it would be interesting if they allow guests to wear robes or anything that can be confused as a CM outfit. But they are selling robes at the merchandise location so who knows.
As for actual SW costumes "dress like Vader, Stormtrooper, First Order Officer, etc" I think they will not allow that on people over 14 years old.
It is very, very easy to Disney bound like, lets say Rey or Leia or Jyn, so we will have to see how far they allow people to go
Now at the SW resort they will actually provide you with clothing that they encourage you to wear at the resort to make yours and everyone else's stay more immersive