I actually mained Pichu in Melee. It felt like a double challenge mode kinda, with Pichu being the easiest to smack away while also damaging himself everytime he used a damaging attack, so winning out against many friends and family with Pichu was pretty awesome.
Despite my fondness for the novelty of Pichu, I'd much rather have Wolf or Snake return. Wolf is more of a reference and homage to Fox's moveset but is too fundamentally different to really be considered a clone. I wish they'd drive that point home by giving him a completely different, non-Landmaster FS.
And I'm still disappointed they didn't give the one who prefers the air an Airwing Airstrike or something. I hate trying to kill with the Landmaster. But since Falco got suck with the Landmaster again, perhaps Wolf can have a Wolfen Airstrike. If they did that, he'd hardly be considered a clone even on a Luigi level.
But I digress from Lucas. Having never played any Mother game nor ever really played Ness or Lucas, I can't say much more about him other than being happy with so many others ecstatic over his return.