I've been doing that trick where I can acquire their arrows after shooting the targets. However there was always one guy that wouldn't shoot and so I killed him; Needless to say he never re-spawned for awhile. When I went on my other account I pushed that same guard a couple of times and they both started shooting arrows not just one. I want to know if that guy can be replaced or if he will ever come back. Or if anyone knows another place that has two people shooting targets at once (not one).

Just curious . . . Why would you have to acquire arrows from guards shooting at targets? They are a dime a dozen in the game. Oops, I stand corrected, they are a dime a 100 in the game. Arrows are more common than the rabbits everyone shoots.
How can anyone shoot a beautiful bunny, or a fine fox? But, I digress . . .

He's probably picking their pockets and replacing their crap arrows with ebony or daedric ones .

For some reason I don't think they respawn. I killed the entire Riften guard on one save and they haven't returned.

_{You'd think they would respawn.
The guards in Markarth respawned after the Forsworn Conspiracy had all of them killed off by the Forsworn after they escaped the prison and went on a killing spree through town.
I thought I was going to be able to do anything without getting in trouble. All of a sudden they were all back again. lol}

This.