Signs actually point to more than one title.
Microsoft is celebrating a YEAR of Rare. Battletoads has some small support because they appeared as additional Shovel Knight content, and some small teases.
Conker confirmed to at least be coming into Project Spark as an episodic release, and as usable content for creators.
Banjo has been teased like four times in 2015 alone, Rare is confirmed to be working on a project that Microsoft says "fans of Rare will be excited to see", and Gavin Price gave a huge, huge nod to it possibly being Banjo Kazooie. There was also an article early this year that Microsoft is planning to use Rare IPs and Banjo was an example listed.
I wouldn't be surprised to see all three announced this year, but Banjo is actually looking more plausible than Battletoads right now. Which is good. Battletoads is old and is only popular for being really difficult in unfair ways. Let it rest in my opinion.
Make the forum great again.