Primals etc are gated behind each other You can only move on to the next primal after beating the previous one then going back to Vesper Bay to unlock the next one (King Mog is it's own questline):
Ifrit (hard) > Garuda (Hard) > Titan (Hard) > Garuda (Extreme) > Titan (Extreme) > Ifrit (Extreme)

WP you can unlock without finishing storyline.
Amdapoor keep is locked behind Aurum Vale which might be a vesper bay one from Nedrick.