Your understanding is mostly right.

Situation 1, if you two married before you get your green card,
a) If he filed I-485 before you get your green card, it's still concurrent filing. Most likely, your two cases will be adjudicated together. Alternative chargeability applies here.
b) If he didn't file I-485 before you get your green card, he can still apply for Follow-to-Join. No 排期 though.

Situation 2, if you two married after you get your green card, he can only apply for family based category 2A green card. And there is 排期