The Wind-up Mithra is probably a meta joke and theres no real relation between FF11 and FF14 but is still possible that the current races evolved from those, like humans from hominids (and kinda salty that Sun Keepers lack their canon feral claws on their depictionm at least Moon Keepers got their fangs). The southern island parts was seemingly datamined from 2.5 so its probably the (open) canon they have as origin