I'm pretty sure a trade very similar to this was proposed like a month ago and was shot down.
That's not enough of a return on Bunting to use their last retention slot on him, especially if the Penguins are taking back Kampf as a cap dump. Bunting has been on pace for 55 points with the Penguins, you're not getting him and having the Penguins retain for such a low return.
Honestly unless Toronto is including either Cowan or a 1st, I don't see anything in their system that particularly entices me to move Bunting there. Especially with the Penguins likely needing to take back a bad deal like Kampf to make the money work for Toronto. Minten is their #2 prospect and he only seems to have bottom-6 upside, which the Penguins don't need more of.