It's a good question. It's similar to the case that no one can hold claims to owning pokemon, for example, especially if they are selling them as main source of income which is I'm doing with my species. They can draw them, make original characters based on the franchise, but they can't own it as something they originally created or anything Nintendo/Game Freak wouldn't allow in their ToS/Copyright statements.

There are many selling designs based on pokemon, but they do not affect them financially, but if it was on my case it would. It's a lot like Homestuck, where the creator who is dependent on his original work needed to come to an agreement of revenue if an artist planned on using his intellectual property for shirts/prints/etc.

You can copyright your ideas when they are not infringing on existing copyrighted material. It's called intellectual property. Doing it outside of my tos agreement would be regarded as theft and I can report it so it goes down with enough evidence and help.

Anyone who doesn't follow the species guidelines I simply talk to them personally and help them iron the design out. I hope that answers everything!