I obviously didnt state my question very well. My question was whether there was anything in the EDP rules that prohibited a player from playing in a different league. I understand one has to pay the cost for each separate league/club. For example, a few years back the NYCFC Pre Development Academy prohibited kids from playing in other league and for other clubs.
As long as they aren't under the same umbrella there's nothing restricting it. Sure clubs can tell you can't, but you can tell them to take a flying leap off a bridge. What they then can do then is make life difficult for your kid if they aren't making all their commitments to practices and games. If they aren't there then their playing time gets cut. That's not unreasonable and only fair to the kids who are there. At the younger ages doing two local teams may be workable, but once you're into leagues with more travel it usally becomes untenable.
Dual rostering is rarely a good idea - besides the time, money and constant inevitable conflicts, it's exhausting for the player.