2 choices, offense or defense?

Epidendrum is better in offensive with additional weakness to slash, your team barely has slash so this skill can shine. More debuff is obvious, her raw stat is higher as well.
Easter Cactus is better in defense with resurrection so you can tank even longer, but her raw stat is one of the lowest for rainbow, even lower than some gold like Snake Gourd. She gets more tips in boss fight with 25% atk boost though.