What has always worked for me with my pups is that I never touch or play with them without having a toy already in my hand. This way he/she immediatly can be forced to play/bite the toy. Your kids might like to do the same as it's probably going to escalate sooner or later if this biting thing isn't dealt with.
As far as humping...it's a dominance thing and you just need to tell him to "go down" and give him a little nudge. Over time that should stop... My boy likes to hump two of his toys but I don't let him, instead those favorites of his are kept in his crate where he can cuddle them instead (while he sleeps). Redirecting is the easiest thing to do for a dog...before it becomes a "habit", that's a whole other animal!
