Yeah, he doesn't worry about staying accurate at all. It's not just with movesets either. Falcon's supposed to be like Batman: showing up out of nowhere, doing the impossible, then leaving without saying much (if anything). Marth's Smash quotes make him a braggart, but FE Marth is anything but. I don't recall Luigi ever being so camp in anything else either, or Wario being awkwardly animated.
I never understood why characters like Marth were made to be so out of character. I understand if there's not much to go, but that's the case here.
Anyway, I'm fine with liberties in movesets, but you gotta be careful with. Ness having Paula's PSI attacks was one thing as Flash and his normals gave him distinction. Lucas, on the other hand, had no real thought into his moves. Yeah, a lot of his canon PSI attacks are stat based, but that's something that hasn't been done before and would've made him stick out in a good way. At first, I was against the idea, but after seeing characters like Jam and Hakan using stat based moves, I thought it was cool if done right.
Well, considering you have a guaranteed way to heal, yes. If it's random and has a chance, it's not broken. For example, if Luigi's Forward B has a 50% chance, it'd be way too powerful.
Adding in randomness is nothing more than Fake Balance. What I thought would work for characters like Luigi and Game and Watch was for there to be a meter system, and these kind of attacks would require some of the meter to do them. This way, you don't need luck on your side so much.
Anyway, if a character has a similar body structure, or the same, they might have similar moves. That's what I meant.
That's a very big generalization. Look at most fighting game characters. Most, if not all of them, tend to be in very good shape and may have different bone sizes, but their very builds do not indicate their moves. You wouldn't think, for example, that Bob from Tekken is actually a very fast character, and then you have Makoto from Street Fighter who is actually a slow walker with very damaging combos.
In short, don't use appearances as a rationalization.