Good episode.
I think so far the actress who plays the new Grimm girl was pretty fitting.
I wouldn't call Adalind dumb. She's just desperate and tries to get back her baby. I'm just afraid, that it will blow back on team Grimm, that they betrayed Adalind like this. Now she's breaking bad again ... :-(
But you are right. Claire/Adalind is really a cutie, and the the Hexenbiest face is quite the opposite, so they could use it a bit less imho too ...
And seeing Theresa as a Grimm, well she said that at least some of the Wesen said that to her before they attacked. So actually no flaw here.
Also, as far as I see the whole Grimm thing, a Grimm has some kind of badassery in his blood like a natural talent. So even untrained they might be some fierce fighters, if they have to fight. Additionally Theresa seems to be on her own for a while already, so she had to learn to survive the hard way. No wonder she knows to defend herself then.