Looking to your last question .. definitely thrust and body angle (as appropriate to aircraft configuration).
One of the exposure exercises I use in the later stages of sim endorsement training is a complete failure of all PS kit, radalt, etc during the takeoff rotation - if I can't fail it from the backseat then I cover up the dial. The crew ends up with absolutely nothing to give them speed, height, etc.
Exercise is to fly the aircraft back to the aid, enter the pattern, and shoot an ILS to landing - with nil assistance from the organist in the back and all in min weather conditions.
Provided that the folk have been briefed as to useful strategies and their basic I/F is OK, the exercise is not a major difficulty - although it might get a bit sweaty for the guys actually doing the work ....