What am I missing in Season One?

There's really two explanations for the confusing sequence of events around Vint's marital status: a short one and a long one. The short explanation is that the episodes were shown out of order, but before blaming Me-TV for this goof, the real blame goes all the way back to when these episodes originally ran on NBC. After the first two episodes were filmed (Mama's Silver and Alien Marriage), Vicki Lawrence shut down production on the show because she felt her character was too harsh and unfunny, so she brought in Harvey Korman to retool the show and help her soften Mama. During the shutdown in production, a lot of things were changed: Besides Mama becoming more likeable, the decision was made that Naomi would be brought into the family to be a thorn in the side to Mama. When they resumed production, they basically filmed a new pilot episode which shows Vint and the kids moving in and then quickly married Vint and Naomi in the next few episodes.

The problem was, they still had the first two episodes they filmed with Vint still being single. So NBC decided to just bury these episodes near the end of Season 1. Watching the repeats, it makes no sense at all but that's because these episodes were edited for more commerical time. In the unedited version, all of the Season 1 episodes had an "introduction" by Harvey Korman playing Alistair Quince. For those first two episodes filmed, Korman explains that they were flashback episodes to a time before Vint and Naomi were married. But these intros were all edited out for more commerical time, so the explanation that they are flashback episodes is gone. That's probably more info than you wanted but that's the story for the confusion.