Yeah, when I have an idea about the character, I tell it to the artist and ask if it fits with the OC. I also ask how the character would react in some situations, ask for dialogue options too, and then work with all that material.
Sometimes my ideas don't really fit, so we look together for a good way to overcome the issues. It's pretty much brainstorming ideas together until I can make a coherent scene out of it.
I like brainstorming ieas with friends so it's pretty fun to me
They allow me to take all the revenue, even if I said I'm gonna share it with them, they just ask me to keep it. Some say that having their "babies" drawn by me and in my work for people to see makes them happy enough U//v//U
So I can't really tell how the profit sharing goes in other cases, but if you have to share it, better be clear about it upfront how much you gonna split it between you two.
My advice is also to always communicate about everything you're going to do with the character, even if your partner allows you to have a free hand in it. Make sure to ask what you are allowed to do and what not. If they're in that collab, their responsibility is to provide you with all the needed information.
If you are uneasy about it, better not push it. Solve the vague directions first until you have a good idea what to do, or else your progress may be slowed down or put to a halt because of misunderstandings.
Good luck, I hope you can have fun
pat pat It's a great experience when you have a patient and understanding partner 