Someone tell Thanos to quit snapping his fingers. Both of the large scale community leaks were false.
With that in mind...
Assist Trophy Confirmed (RIP)
Spirit Confirmed (Also RIP)
Rex (relegated to Mii costume double ouch)
Already deconfirmed (Old RIP)
Rayman (via being in Brawlhalla instead)
Survivors for possible 5 DLC slots
Ken (expected, but not unwanted)
Incineroar (Oh boy, a _tenth_ Pokemon rep, how exciting)
a FUCKING plant (as a pre-order bonus, lul)