Went a little overboard on the third-parties, didn't you? We do know there is a maximum of two more of those, after all. Plus one of those is impossible - Banjo-Kazooie belong to Rare, which is owned by Microsoft, who would surely never give Nintendo permission to use them.
5 Fire Emblem characters? Bold, and almost surely over what the actuality will be. 5 Zelda and 6 Mario also seems to be high, albeit merely by 1 each. 4 Star Fox also seems overly optimistic, given its a smaller series and seems to be past its pinnacle of popularity. And of course, 53 characters total is definitely high - frankly, we'd be pretty darn lucky to pass 45, since at that point you're looking at having as many newcomers in Brawl as there were total characters in Melee (factoring in those leaving).
Knock out Banjo-Kazooie, Ray Man, and either Bomber Man or Mega Man from 3rd-party; either Midna or Vaati from Zelda; either Bowser Jr or Geno from Mario; Wolf or Falco from Star Fox; and Hector and the Black Knight from Fire Emblem; and you've got a pretty good line up. 45 characters total, 5 Mario & Pokèmon, 4 Zelda, 3 Star Fox & Kirby & Fire Emblem & DK & Earthbound, 2 Metroid & F-Zero, and singles from other series. Oh, but you need an Animal Crossing character in there somewhere - they've got a unique icon, something only series with characters get. Knock out one of the Earthbound characters for that most likely (probably Ness, since it seems most Earthbound fans expect Lucas to replace him).
Zevox