While I can definitely get behind Kanonen going to a Cedar Fair park, I highly doubt it will show up at Knott's. Particularly in the spot where Boomerang stood, I have a feeling the GP would simply think of it as "mini Xcelerator" and that it wouldn't get very much attention. Additionally, Intamin Accelerator coasters are widely considered among the most expensive coasters to maintain, so I doubt Knott's wants a second low-capacity high-expense ride.
That said, based on what I've heard from a generally reliable source, I do expect the new ride to be a launch coaster. While they wouldn't tell me exactly what it is, the hints they gave me sounded very much like a custom Mack launch coaster comparable in size and scale to Maverick. Even if that ends up not being true, given that construction is beginning in late April I suspect we're looking at a large coaster, large enough to cover the entire Boardwalk and not just the area formerly occupied by Boomerang.
I agree, I hope this is going to be a large roller coaster, not necessarily in footprint but height and or speed. If it were me I would be pushing for a dive coaster 200ft+ with an Albatross theme since were in the "boardwalk area" Like "Albatross" or "The Great Albatross" bird themes just work for diver coasters.