I'm of the camp that if Geno gets revealed as a costume, he likes 99% dead (even if it's a barely changed outfit). Otherwise why not delay his costume for his reveal? People may say why buy the mii costume when the character is already playable, but that didn't stop Erdrick's mii costume coming with a fully playable DQ Hero. Sure you could go and say that you're wearing Erdrick's ARMOR, but you're just pushing the goalpost at that point.
If the rumors for pass 3/bonus are true, then they would've just delayed the costume till then (assuming Geno is playable). So if the costume returns now I think he's just dead even for a potential pass 3. Not to mention with each reveal, competition gets tougher.
So far based on what leakers have heard Dante, Ryu, Crash, Lloyd, somehow all have a very good shot/are "in". Yet, literally none of the characters so far are commonly "predicted". Even if we assume all slots will get filled, that leaves 3 left; fill in 2 of them with Geno and Master Chief (since he was also heard a ton). Also throw in someone like Waluigi/Reimu/insert RUMOR here, and we have all 7 slots.
No offense to the leakers, but at this point it's far better to just wait it all out rather than pay attention to leaks because none of the common rumors for FP2 have come true. Heck, I wouldn't be surprised if none of the above got in. Nintendo could just be really good at hiding stuff now so it's not really worth paying attention to insider "hints" apart from literal seconds before a reveal.
I'm probably hopping off until Thursday to see how things play out, I think Geno will get costumed; but maybe a miracle will occur and he doesn't, in which case hopefully he becomes playable later.