Yoshi-P stated the Qiqirin at some point were going to be an actual Beast Tribe but they decided to go with a different group instead.

I'd currently say for ARR ones they are pretty much done, however with 6.0 most likely taking place back on the Source there could be a way for the Qiqirin/Gigas to be a tribe if they resettle them for Garlemalde. I think the Qiqirin are naturally native to Eorzea but that doesn't stop them from going across the sea to trade so it could be within reason they have a settlement in a 6.0 area.