If 1 PSU dies only the board it is attached to shuts down.
Are you running them on the same circuit in the home or splitting them up? Probably just 13-15amp load right?
You can run them on 1 circuit as long as the circuit is big enough, which all will be if you only have 1 unit.
for 110V you can have 1 741 on a 15 amp circuit, or 1 821. 1150w/110v= 10.45A , 1200W/110V= 10.9
If you are going to be running multiple machines I suggest going with 240v circuits.
That sucks about the Canaan AMS, but you could look into awesome miner, you pay for it but I've heard good things. I myself don't have the problem of managing that large of an operation... mini mine, lol