Well the wiki
https://wiki.smutosaur.us/FoE/Main_Page#Companions
lists the following as companions:
Asche- presently not recruitable but functions as a mission giver- location Rigard Magic shop
Cverte- presently only recruitable for one mission [Bull Tower] - location bandit camp
Gwendy- presently only recruitable for one mission [option 1 of Big City]- location Gwendy's Farm
Kai/Kia - can be recruited as soon as you enter Eden
Layla- can be recruited at Gwendy's farm after defeat of Orchid
Mayflower- not recruitable [not sure she is even in the game yet]
Miranda - presently only recruitable for one mission [Shifting Blame] - location Rigard Gate
Terry - recruited via mission Guilty Conscience
Zina- presently not recruitable, if she has been implemented you will find her in the Spitting Lion
As for Jeanne you meet her after completing the Mage's Tower mission [hint in the palace in the city]
have fun