SOLVED. 70s-early 90s YA fantasy with female character whose name starts with Z, a red-headed male character, horse-like deities. [s]

[Autumn]

Ok, I've done a tonnnn of searching. Despite similarities, not Valdemar or the Mountain's Call.

Also forgive my super vague memories.

Two girls emerge as protagonists in this series. One's name starts with Z, something like Zephy. The other's starts with maybe a T or a P. Tai? And then there is a red-headed guy who loves T-girl, but ends up together with Z-girl (his good friend but not someone he deeply loves) for some reason instead.

Z-girl is capable of some kind of magic, can communicate with what I think were horse-like deities, who did not appear fully, more like beings of light? From another dimension or world. T is also capable of some kind of magic, or has great power that maybe hasn't emerged yet, and she's being pursued? In one of the books of the series, the T-girl ends up imprisoned in a tower with red headed dude, and he's being tempted by some evil power to have sex with her to fulfill some kind of prophecy...?

I read these when I was 12 or 13 in my local public library in Fairburn, Georgia (outside Atlanta) and can't remember the covers. It would've been 1994-1997. The books didn't seem super old but not super new either.

And that's all I've got! Phew. Not much to go on. Thanks for any help you can offer :)

[Cupcakedoll]

and series, I think they're what you're after.

[Autumn]

ZOMG YES. Thank you thank you. This has been eating at me for years! Now to find and buy them all.