I'll go with Simon Belmont, I think he would be an easy one to make and as for Final Smah options he has plenty, I mean every Item he has (whip, boomerang, axe, etc.) has a possible final smash.
Another one would be Isaac from Golden Sun and his final Smash is pretty easy to guess, Judgement.
Also this one I feel would be great, Alex Roivas from Eternal Darkness, OK so here is how I think she could work, so against the final boss in the game you use every playable character as ghosts by basically transforming Alex into them, so I think that besides the Magick(that is how they spell it in that game) you could have her use the ghosts as attacks like right+B could be a dashing Karim which attacks with Ramdao and would have short range, and be could be Michael Edwards (the firefighter) shooting a grenade from his grenade launcher,etc. you can use you're imagination but I think she would work pretty well, also by including her you could also include Augustus who would be a terrific playable villain.