I'm sure they will attack you, i remembered someone who attempted to
create street fighter (I think), with m.u.g.e.n and he mailed them and
also many examples of freeware fangames like street of rage and chrono crises, prevented to be released for the public due to copyright issue..
this just an examples for freeware projects, and for getting profits i'm afraid you will lead yourself into trouble with CAPCOM, perhaps you
can still make a clone game with megaman elements but different story
and characters, if you still love the idea.