Right now Primals are linked to Beastmen Tribes and therefore need some kind of "logical" connection, hence why Ifrit is Amal'Jas Primal, Garuda is gonna be Ixalis Primal.

My guess for later on, Titan for Kobolds.(since his design was in the dat. files from the beginning)

If normal civilisations might have Primals as well, my guess would be...:

- Bahamut/Odin for Ishgard
- Leviathan for Limsa
- Siren for Gridania
- Ifrit for Uldah(after defeat of the Amal'Jas?)

- Gilgamesh for Ala Migho (considering their culture?)
- Alexander for Garlemald (since it's a "mechanic" based Primal?)