How come brands passive proc's all stacks on frostfang while teemos E nor R can?

E is an on-hit effect and doesn't apply spell effects. R hasn't been applying spell effects since the last patch, which is probably a bug.

Because Teemo is a scumbag champion and he should be deleted from the game. This is Riot beginning to phase him out for that.

Because it makes support brand as well as support morgana and Cass work but no one likes having to deal with teemo.