The the type tackling Seattle teaches is called "rugby style". Urban Meyer has adopted this at OSU.
Interestingly, Malik Hooker''s tackling using the rugby style was criticized by scouts prior to the draft.
A lot depends on what the coaches want to do with Butler. He is our best nickel CB IMO. Will the coaches want him to swing back and forth between nickel CB and safety depending on down, distance and offensive personnel? Seems reasonable to me.
With all the young DBs it might be tough to get get all of them the reps that they need to best sort the various roles out. But that is what the coaches are paid to figure out. I wish them well.