do season passes for magic mountain cover discovery kingdom?

If you have that included in your pass. You can check online on the membership portal.

The season passes used to let you do that but this year they changed it so now you have to buy one of the memberships and not just a season pass.

I beleive that's a separate pass/ticket... I don't think there added on the season pass. For California you have six flags and hurricane harbor which you can get if you buy both parks plus free parking. But it's extra.. You would have to check in your portal..