Are There Cross Breeds In FFXIV?

[Theodric]

I'm more interested in if the inability to manipulate aether is inherited when breeding with an aether-manipulating Hyur or not. Does he ever mention it?

He doesn't bring it up. I'm very interested in learning how that works too since I'm a role-player who plays a Garlean half-breed myself. (A shocking revelation, no doubt!)

My current tentative theory is that Garlean half-breeds can manipulate aether but their ability to do so is severely dampened and leaves them feeling very ill.

It's only very recently that we learned about Garlemald's hierarchy and what the 'third eye' actually does. The former was discovered in Gubal and the latter through a Q&A session. I'll make a mental note to bring the question up next time we get another lore Q&A.