Eddie, if you fly PT6 gear, if you ever have the chance to shut one down in flight give it a go and have a look at your N1 (or Ng if you prefer that term)- there will be rotation. Been there, done that, and the sims replicate it too.
I'm working from memory here as I don't have access to my manuals right now, but the air start procedure (no starter assist) calls for a minimum airspeed to be reached. Do you know why? Well, in very simple terms, this is to force air into the engine and rotate the N1.
Megan, even with failure of the rudder boost the B200 is very controllable. It is best thought of as an "assistant"- it doesn't give you a massive bootfull of rudder but rather just gives you a bit of rudder to help you out in an asymmetric situation. It's a 10 day item if failed so not exactly critical.
If your calculations on prop rpm are anywhere near correct, that intrigues me.
Comp stall, yes the lack of CVR is very disappointing, the investigation probably wont be able to uncover many useful facts as a result.
One thing I find interesting from the report is the flap position. 10 degrees is not a correctly rigged position. If memory serves me right, the Takeoff/Approach (40%) position is 14 +/-1 degrees.