So when you took the queen out of the hive, did you take out any uncapped brood as well? I'm familiar with the Hopkins method, never done it myself tho. Seems to me you'd want to set your frame over the top of a queenless hive that has no hope for making a queen in any of the frames of brood inside the hive. That would mean no uncapped larva or eggs in the frames, and no queen in the hive.
Bringing in pollen is a good sign in a hive, usually meaning open larva or if not, then a laying queen beginning to lay eggs so pollen is needed in preparation of larva. If you've got open larva in the frames then bringing in pollen is good normal thing to see. If there are no open larva other than on your hopkins frame, then that is good sign also, they are bringing it in for making the royal jelly to feed the queen cells they are making.
20+ years, raise my own queens, feed when needed, I treat but have not perfected varroa management yet.