I would recommend Evie (with a staff) because:
- with some basic dodging skills it's pretty easy to avoid most attacks (and Mana Amber is an easy fallback plan)
- she can deal damage from outside of the range of most attacks
- she is extremely versatile in her abilities - from reviving, to healing (via erg crystals and corona), to granting attack opportunities (with freezing and Reverse Gravity), to damage dealing
- she has a lot of cute sets and a few that are exclusive to Evie
- and finally, she is really fun to play!
of all the above, point #4 is definitely the most important. :skip:
As an Evie player, my best duo partners have all been Karok. It seems like their battle synergy is good, so if she goes Evie, Karok would make an excellent choice for your alt.