There can be meta-humans that have multiple power classes. Both of my characters actually fall under three different classes, although each of them have a power class that is particularly much stronger than the other two.

I'm currently trying to come up with ways to make them get stronger over time, since that's going to happen to almost all the characters. Atticus has powers that I already have ideas for, but I have multiple options for Codi. I could make Codi's bacteria or Reef's venom/ abilities more powerful, or I could abandon mutating the urchin and chemical aspect and give Codi (The human part of her) a new form she can switch into, although like Atticus, there would be a period where she couldn't change, unless her life was in immediate danger. I kind of like the second option more, since for the most part every time I have ever made a character whose powers incorporated lethal venom or toxin with no potential cure, people never fail to dodge or escape those attacks in some form or fashion (One time, a person even said that their character was hit by a claw, although the attack was actually lunging forward with venomous fangs). Those are my ideas, right now. 

Does anyone have an opinion about the second idea? If I choose that one, I'll have to write a very long, detailed appearance, and I don't want to do that if I can't use it.