Keep the parents out of it. Let the players figure it out.

I have considered all kinds of punishments I think would be appropriate.

I think the most effective thing would just be to forfeit every game to the Astros and never play them. No one should trade for an Astro player or allow the Astros to pull players from their own roster. The Commissioner and the Astros owner should get the message soon enough. If they try to sanction the forfeiting team then public opinion will turn against the Commissioner even more I believe.