Welcome back! I do love living in Pittsburgh. I live in the North Hills and work in Oakland.
There is a babywearing group that meets once a month - the third Saturday, I believe. It used to be part of NINO, but I think NINO disbanded or something. But the group is still going. MonteMama (the owner of thebabywearer) and another mother run it.
Since I live in the North Hills, I can't help personally with the pediatrician information, but I know a lot of moms who lean toward AP/NFL who use Dr. Hildebrant (not sure if I'm spelling his name right or not). He's in the East End near Trader Joe's - Point Breeze or Wilkinsburg. I see a pretty mainstream pediatrician near my home, but he's fine with us not vaccinating. We just sign a refusal when we go. We are hoping to send my boys to a private school and they are fine with an alternative vaccination schedule, just some papers to sign. I haven't dealt with public school or the state waiver yet, but I hear it's pretty simple.
There is an AP meetup group. It was pretty slow and only had a few meetups each month, all during working hours, so I left it before my membership fee was due. But if you will be a SAHM, it might be something you'll want to look into. I belong to a big mom's group on meetup (Burgh Friends and Family). There are all kinds of moms there, some more mainstream, some more AP, but there are tons of activities and get togethers and I've been very pleased with that group. Membership is free until June also, so you can always check it out with nothing to lose.
Feel free to contact me if you want more info on anything else. You'll be in a nice area in Squirrel Hill!