How many of the new dungeons are optional?

[Amelia_Pond_Behemoth]

I'd like to unlock them all anyway, but I only want to do the quests to unlock them, and save the other quests for another job. How many dungeons are unlocked through the main story, and how many are side dungeons?

[Blanchimont]

Only "The Dusk Vigil" unlocked at level 51 is optional, but you have to complete the dungeon to unlock flying for that region. Following that are 5 required dungeons and 3 required trials. 2 post-game dungeons are unlocked after clearing the story. The first post-game trial require a premade 8 man party so I don't know how many trials there are.