I think you are doing all the right things. Letting your 8yr old feed him, and obey her commands will let him know she is higher up the pack order than he is.
Putting him back on the leash when he misbehaves like that is good too, but you may want to take it one stage further. Put him back on the leash, say nothing, and take him right back home. No attention for a while either. Basically, send him to the "dog-house!"

He will soon learn that this kind of behaviour results in termination of his "fun time"
Good luck!