"It appears good old Conker has been replaced with Tiny Kong (possibly for legal issues)."
I doubt that legal issues are entirely the reason, since Conker becoming a perverted, greedy, violent, swearing drunkard wouldn't exactly look "family friendly" when paired up with Diddy again.
Tiptup, though being a Rare owned character, appears on the map. Banjo could be removed given his confirmed Xbox 360 release (even if Tiptup shows up, he'll likely be a minor NPC like the other Banjo games), but it looks like all the other characters are safe.
And a recent update to Rare's official website describes new characters, vehicle customization, and track creation. Pretty major additions. Here's to hoping that Dixie Kong's one of them.