https://www.youtube.com/watch?v=-bZxO5Dn9x0
Looks like a lot of fun
Billy Dee, Kelly Marie Tran, and Anthony Daniels are confirmed to be reprising their roles (and it's kind of obvious with Williams here), and the Clone Wars cast is pretty much all there too (That's definetly Tom Kane's Yoda as narrator)
It sounds a lot like that's Mark doing the Joker voice as Palpatine pretty much.