Would love to see that--Banjo and Conker are my favorite Rare characters, and ever since Diddy Kong Racing, felt like they belonged together.
I will say that I don't expect any more rare characters, either Microsoft or Nintendo owned. This fighter pass looks to be third-party only, So I'm just going to count Dixie out right now. And I don't expect anyone company to get more than one character, and if that did happen, I would expect it to be Geno as a special exception.
But if I were to have my pick of the litter, I would go with the Battletoads. Something about their movements in their own game has always made me feel like they're perfect for smash. They've got a jab combo down, many different options for smash attacks and tilts, Dash attacks, grabs and throws, the only thing even remotely tricky with the B come up with their specials, but I think soccer I could do it.
that being said the only character I'm all that attached to from rare is Conker, but I don't think he would work very well in Smash.
I don't expect multiple characters from the same company as well, though I could see some exceptions. Geno, I feel is the most likely--while owned by Square, feels like to many like a Mario character (like Banjo & Kazooie feel like a Nintendo character). Doesn't change the legal realities, but I could see that being a last DLC character. While not huge for a general audience, I feel like they would put their most marketable characters first to sell the pass, and leave fan favorites for the last couple, Banjo & Kazooie being in the middle. I feel like that's a safe expectation--would disappoint most people, but would go over well with Smash fans.
A second character I could see is Sora, as it's owned primarily by Disney, not Square. Would be a good character if they wanted to "top" Banjo, though I would expect them to show Sora closer to the first 3 fighters, again, to sell the pass. And I could see Master Chief, as Banjo & Kazooie are more Rare-oriented, Master Chief seems like a next step after that, and would break the internet. While I'm skeptical of multiple characters from the same company, Microsoft is slightly unique only having one character--for all we know, the next two characters could be Bandai Namco and another Microsoft character.
I expect, however, only one character per company. I'm rooting for Crash, but I'm also doubtful of another Western-owned character. But, thankfully, my dream pick is in, so I can sit back and relax. I'd be fine, personally, with no more leaks--would be nice to go into the final characters fresh, as I no longer have the lingering anxiety about Banjo & Kazooie--though, I know for others whose characters are still not in, it's not over for them, and welcome them if they happen.
EDIT:
I honestly think Conker's Bad Fur Day is kind of overrated. Not bad by any means, but there are a lot of segments where the gameplay just isn't fun and you keep going just to progress the story. I'm thinking Bats Tower and that horrible underwater segment (I keep wanting to call it Down the Drain but that's from Earthworm Jim, innit?). Even some of the good segments like It's War are practically unplayable in spots.
I have to agree to a certain extent--I like the character and what he represents more than actually playing his game. Feels sluggish, not a fan of story-driven games where you're forced into a certain progression. I appreciate the character for the humor and having a mature Nintendo icon. Would love a new game, with better controls, and more freedom in the actual gameplay.