Lots of medical options to choose from- a little overwhelming, actually. I don't use mine for much more than the basic stuff, but if you're savvy about what you need, you should be able to find the one that best fits your situation. Most family plans cost in the neighborhood of $200 pre-tax per paycheck. Some others might be able to sound off about specific plans if you share what you are comfortable sharing about your family's needs.
Vacancy bids are not required to happen on any sort of schedule. With movement as it has been here the past couple years, we usually see a bid around every other month. EWR is very junior, as well as SFO. I would say the ability to get EWR as a new hire is likely, and practically guaranteed within the first 6 months. If there are no vacancy bids open, you also have the chance to base trade each month with other pilots in your same seat. There is usually some trading back and forth among East & West Coast junior guys. You have a few months of training before you get online, so if you do end up getting SFO in class, you've got a pretty good shot at getting EWR before you actually have to show up to fly.
As for RSV, all lines are long call with 12-13 days off. The company can convert you (on a day to day basis) to short call or field standby (on call at the airport) as many times as they want, with some financial incentives if they convert you too many times without using you to fly. You have the ability to aggressively pick up trips and short-call assignments. As it is at most airlines, reserve is much better if you live in base and know the contract.