he might just be getting old. :( My goldfish does the same thing, and he has lived for quite a while. Keep a close eye on him for a couple of weeks, and see if he improves. if nothing changes and he is still eating, i'd say he's fine. :))
I know this may sound agressive to some extent, but knee him in the chest when he jumps up. And if he thinks he can't get away with it with you and he can with other people, then invite one of your friends over and have them do it too. Cures the problem very quickly. :)
What you're doing now seems to be okay, but twice a day is better. About 3-4 pellets of food in the morning and at night is best.
if you go away on a trip, then yes, he will be fine while you're gone for a day or two. If you are going to be gone for longer, then you should get these small white...
It should be split 50/50! And the mother needs to be in as much comfort as is possible during labor. The conditions that you have set up seem to be the best choice. But just because she has the female doesn't mean she gets 75% of the pups. Without the male she wouldn't have any.