Deep stalling isn't a common thing in model designs except on very special layouts like deltas or extremley low aspect ratio designs. In your case I strongly think you're worried about something that won't happen. By the time it fully stalls the model will be flopping around from the loss of lift and not from the loss of directional control.

Our models can't achieve the higher angles of attack that the full sized stuff can. The Reynolds number effect limits it. We're lucky if we can get up to around 8 to 10 degrees before it stalls.

I also think you're right in that the pusher prop would suck in a lot of the turbulent airflow at lower speeds and it should help out a little. Also the prop disc DOES add to the fin area but I'm not sure by how much.