Nathalie, uncontested. Khalida was best girl in Avadon 2 but she's, I dunno, too written out in Avadon 3? Plus, initial dialogue describing her having plate armor and a sword always tilt me hard.
Classes? Sorcs. Can go ham on INT. Insane damage type coverage. One of the best defensive skills in the game, which costs peanuts to cast and actually has a chance for you to do another action! Though I'm currently leaning on a Shadowalker playthrough when I get the full game. Less hassle on deciding where class specific equipment goes to.