Not on Capcom's side or anything here, and like you say, they'll probably turn a blind eye to it because crushing it would burn any bridges they have left with their fanbase. But I do think they could easily win a lawsuit against Inafune here if they wanted to. Mega Man was certainly his idea, but unfortunately his brainchild isn't his anymore, and creating something that is essentially Mega Man in all but name when he isn't legally entitled to is risky business. There's a precedent for this kind of stuff, as Nintendo won huge damages back in the early 2000s against Tear Ring Saga, a game created in nearly identical circumstances (the creator of a series, in this case Fire Emblem, leaves and creates a game with extreme similarities to his previous work), and Tear Ring Saga was really no more similar to Fire Emblem than this looks to be to Mega Man.
In any case, hoping Capcom decide to be cool about things, as it looks like a lovely throwback to Inafune's earlier work. Still, if Capcom decide to fight this battle, it looks to me to be almost certainly one that they'd win going by how the game looks so far. :/