What do you mean not a misspell? I'm not trying to be a bitch, but I'm pretty sure Fenix isn't a legit name. Phoenix would have a lot less confusion. I thought it was meant to be Felix when I first read it. Elias is a fantastic name, and I'd be a little sad to see it followed with Fenix (sorry, I am a major name nerd).
Other options that have a similar style to Elias and Phoenix in my opinion:
Julian
Leo
Miles
Pierce
Dominic
Fabian
Adrian
Clement
Jasper
Ezekiel
Julius
Apollo
Raphael
Luke
Peregrine
Levi
Ulysses
Best of luck!