"I loved your wedding, it was very lively."
Translation:J'ai adoré votre mariage, c'était très animé.
My dictionary says that the appropriate usage for "vivant" is a lively account, or a lively style.
Whereas "animé" is for places, scenes, atmospheres, conversations, music and evenings. (And although it's not listed, I think we can safely add "events" to that list.)
I also don't see where you're getting your Collins reference from. Collins online gives me "vif/vive" for a person, or "animé(e)" for an event or discussion, although it does list a lively style or portrait for "vivant".
I suspect that "bringing it to life" is not what "lively" means in this sentence.