PYSA and OYSA requires coaches to carry around waivers and emergency contact info for each player. You can just take a photo of these documents and attach them to the player profile (mark them private) in TeamSnap.
TeamSnap is not cheap, but can bill your team parents for the season cost through the app. The cost of transactions is not cheap either, but if you bill parents more than a couple times a season (tournaments, equipment), it is worth setting up.