Yes, you can do the baby swap. Entering from Fantasyland side, right before you get to the covered area there is an exit gate and they had us board there, dh waited there and when we got off, he got on. HTH!
We always use Baby Swap on Matterhorn, but have always gotten a pass from them. We are instructed to use the handicapped access area to redeem the pass, but ALWAYS have gotten one.