Did you see PG Staff's video of his grand daughter hitting a golf ball? Might want to be careful with the throwing like a girl thought. She can probably bring it 
As to your actual dilemma, IMO, your most difficult task will be getting them motivated if they don't have a desire to improve or make any real effort. To be honest, I'd start by having a video practice and showing them the original Bad News Bears. Then tell them that that's them (now), but if they want to dedicate themselves to truly working to be better at the end of the season than they are now, you'll work as hard to get them there as they're willing to work.
Then, back to the basics. Teach them how to throw, catch, hit run.
Then, set clear and achievable goals around the fundamentals that you want them to achieve. Set some rewards if they achieve them (maybe another movie night with them to watch Major League, etc). Try to find some combination of motivation and fun to see if you can light a fire inside any of them. I wouldn't expect miracles, but if you can leave better than when you got them, I'd call it a successful season.
Best of luck.