I'm still new to the social media side of things when it comes to art and haven't quite grasped adoptables yet. Isn't non-profit fanart already ok under normal copyright? Or is this more of a support the artist first type deal that just comes with a noncommercial community-based claim to the design?

I'm not really sure what is it you are asking, I'm sorry ;w; could you please reword it for me?

Basically a predesigned character by an artist that becomes “yours” when you buy it and then you can do whatever you want with it (option B in your question)