The Raptors gave up their pick this year to get Lowry, though. So I don't know that they'd want to give him up so quickly, especially for a guy with issues like Tyreke Evans.
I think it might be more realistic to try to get Calderon from the Raptors in a 3 team deal like this. Playing beside Bradley and backed up by Cousins and KG, Calderon might not be such a liability. Plus, he's been extremely efficient this season and he's one of the few guys in the league who can come close to Rondo in terms of the ability to really capably run an offense.
Calderon is on an expiring contract and is blocking Lowry, so I imagine the Raptors would be willing to give him up for considerably less than what they'd want for Lowry.