I enjoyed this, despite finding some of the extra letters quite tricky. For example, I could think of a dog which made the clue, but not the instruction work in 19a.
Also 28a - 3 similar words (albeit, one archaic) reliant on a single unchecked letter all of which fit the definition. In these circumstances you want the clueing to be cast iron but that synonym for threaten seems a bit borderline for me.
However, nice theme and neat solution. Thanks, Dash.