50/50 Custody doesn't usually work well and really isn't in the best interest of the kid. Kids need routine, kids need one place to call home. Request a mediator for the custody nitty-gritty, it's cheaper than an attorney and they will likely have opinions and suggestions for stuff you didn't even think about. It also might be helpful to "try" certain arrangements and agree to re-evaluate everything in 6 months or something. What works for the one year old, won't necessarily work when the kid starts school.
While his family watching your kid may not count toward custody, it should count toward child support (IMO). What would you have to pay for child care if his family wasn't picking up the slack? Talk with your attorney/mediator, but you may want to agree on a number for child support and then figure out what can be counted as credit (or partial credit) toward that, like child care, medical, rent or mortgage payments on your residence, etc.