I actually read a really helpful article on something that would help address one aspect of this just last night looking up the cat biting thing (from a different thread).
I'll see if I can find it, and I'll share the basic idea after these others.
Do you have a lot of tall vertical space? When our Ming Loy wanted to play with Flowerbelle, and Flowerbelle wasn't in the mood, it really helped to have places for Flowerbelle to flee "up."
Play with your younger kitty as much as possible. He's got a lot of energy, and the more you can work it off, the less he'll be bothering her. Break out things that really get him running around, like da Bird, Neko Flies, or the red dot (laser LOL).
As much as you can over the next few weeks/month, whenever he pounces/chases her, try to redirct him with a toy. The idea is to help him learn that she's not his play thing. Reinforce his "redirct" with lots of praise for playing with the toys rather than with her. I don't know how much this will help - I just know that negative reinforcement doesn't work nearly as well as positive reinforcement.
Get a treat ball that you can twist the size of the openings so that treats do come out, but it takes a lot of work to get them out.
Look into getting interactive toys that don't need you - automated things that are safe to leave out for him. Most good ones cost a lot. Rather than look up links again, I'll see if I can find any threads/posts that have the links, so I'll get back to you with this. But you can google "interactive cat toys" and probably find some good ones. If you can afford them, just make sure to rotate them so he doesn't get bored of them.
Put up perches of some kind on a lot of your windows. If you can, put a bird feeder or squirrel feeder up outside one of them. We bought a Droll Yankee clear plastic bird feeder that sticks to the window with suction cups. It is TOTAL cat TV.
OK. Now to the article I read last night. I know he's playing, but see if maybe this would help. Is part of his play a dominance thing? If so, part of how you can help is by not defending your girl kitty, but reinforcing his role as alpha (if that's what's going on). So this actually works in conjunction with the redirecting him to a toy when he's chasing her - instead of telling him "no" or something, you grab a toy, and give him the attention. It sounds like by running, she wants to be lower in the hierarchy. And when we scold the playful or aggressive kitty, and then give attention to the lower-on-the-totem pole kitty, we just keep confusing things for THEM, and reinforcing the more dominant kitty's NEED to be aggressive to the other kitty.
Just make sure to give her a lot of alone time, to reinforce how much you love her.
