Sticks and lava chews are fine, and even good to give kits and adult chins all the time. You might want to look into one of the vendors on here for wood though, most chins don't really like the store bought ones and they are very expensive, you can get a whole pound of sticks for the same cost as a handful of pet store sticks.
Male kits are generally weaned at 8 weeks, otherwise they can breed the mother or his sister (yeah I know, young!). I'm not sure on the proper weight, but from the sounds of it he might be big enough. He will be upset, he has to leave his family, but it's needed, and the mother could sense this and that is why she is attacking him, telling him it's time to go away. You do want to make sure the male is at least 6 inches away from the females though, they can breed through the bars if it's less then that.