So normally, an ally that goes to 0 hp stays there until healed, and can't act until they get above 0hp. Regen was erroneously kicking in and essentially reviving her every turn. Fixed now, thanks for the report!
Maya patpats are the way and the truth, and Metatron is rapidly becoming team big sis lmao.
Your primary stat/stats should always be capped for easiest progression, I usually just set them to auto-grow. The rest... kinda depends on what you're doing. 10 focus is enough for 1 turn cooldown reduction, or 10 insight lets you ignore most armor/resistance. 5-10 vitality also gives access to some great traits.
You can respec as needed, it's a bit cheat-y but the important thing is to have fun.