I don’t want to crush your fan spirit, so… while I do NOT think Ty Lee is related to Jinora, the only way that would be possible is if Pema (Tenzin’s wife) is somehow from the Ty Lee line. 

It would seem more likely to me, though, that Jinora is wearing a Air Nomad twist on an Earth peasant hairstyle, and that’s what’s connecting Jinora to Ty Lee in your mind.

They do look similar, but I want to assume that whatever happened between A:TLA and LoK wasn’t just the characters from the first series mixing in a blender to make the characters from the second series.

I loved Ty Lee’s energy and spunk and general optimistic attitude, and would love for that to come into LoK in an organic way. However, making Ty Lee somehow part of Aang’s extended family seems far-fetched.

In my HUMBLE opinion, of course.

-Da7e-