So... an ARMS character is confirmed for FP6. We just don’t know which one.
I still kinda doubt Spring Man as he’s an AT. Granted, Chrom is playable while still also being in Robin’s Final Smash and victory screen, and Mario appears in one of PP’s victory screens. There’s also some ATs disabled on stages, like Alucard for stages with reflections or the Moon on Mementos. But... I just dunno.
ribbon girl could happen, and it would be a beacon of hope for Rex, Cuphead and the like
it could be a Spirit promotion too, and Min Min and Twintelle, ARMS’s two most popular characters, are Spirits so if any promotion were to happen I think they’d be the easiest
or they could go with someone who’s neither. Only ppl that come to mind are Mechanica (breaking the “no side characters before protagonist” rule) and Dr. Coyle (breaking the “no villains before the heroes” rule)