There's really no way of knowing who will be competing until you get there. Schools just announce their meets and other schools call and request attendance. They never announce/post those who are attending. You might want to call the coach a few days before and ask.
As for V/JV, each meet is different. Some schools have combined meets, some don't. It depends on how many teams they allow in. Most have combined varsity and JV meets with boys/girls. Not all, but most. Larger schools like to separate boys/girls so the meets don't take forever.
Make sure you look on the schools athletic website for scheduling. If it's not on there, email the coach for one. If he/she doesn't reply in a timely manner, contact the school's athletic coordinator. They'll send you one.
Good luck!
4951