The matchmaker brings your tama a mate. So, your tama can't marry another tama you connect with if it has already married one the matchmaker brought you. Is that what you were asking?
They have babies when they're married. The having of babies signifies the tama's marriage, I guess. They don't have a wedding and actually get married. That would be cool, though!
um, well the matchmaker cab present your tama with a mate and you can choose to mary it, yes, and you can also choose not too. you can't mary twice with 1 tama, though
Aww that would be cute. On the v4.5 or the v5, when a Tamagotchi gets married using the matchmaker or another Tamagotchi, they should have a little wedding song while they kiss, then fireworks, then the babies.