By engine failure recovery procedures, do you mean actually switching it off and restarting it at altitude? I wouldn't want to switch off a perfectly serviceable engine, however I do occasionally recite my immediate action points and reach for the switches to simulate carrying out those actions.
If you mean practising landing without using the engine power, I regularly approach airfields at 2000 feet and ask for permission to do what the germans call a "ziellandeuebung" (practice forced landing) and if they don't have much traffic in the circuit, they allow it so with respect legality, it's allowed, indeed at our club, it's highly recommended to practice it whenever we can.
Having said that, although in my case I just close the throttle and leave the engine on idle simulating an engine failure, I have seen an ultralight come in with it's engine completely off, then restart on the runway so yes, it's something practiced, although I'll not kill my engine, I'm not that foolish because if someone just rolled out onto the runway as I come onto a short final, I'd like to know I can go around even when practicing a PFL.
Concerning stall recovery techniques, I'll do them now and then but only if I'm alone or the other people in the plane are warned about what to expect - hearing the stall warning horn go off and the plane dropping can be unnerving for the uninitiated. In my mind, not practicing might lead to you taking the wrong action at the wrong time so practice makes perfect.....