I think
Alexandria is the best "
Alex" name, then
Alexandra.
Alexa and
Alexis sound like unfriendly teenagers to me. I like
Ren. I'd also like
Lotus as a middle name, although it's a little more cheesy.
There's also
Charis,
Charissa,
Larissa,
Alessa,
Alessandra,
Iliana,
Laurel,
Chanda? Those might fit with your name style.