I really didn't understand what's your main idea for your vid. If your planning to make a kind of love triangle with Ranma-chan, Ranma-kun and Ryoga; just remember the video is about yaoi and the pairing you chose is Ranma (boy) and Ryoga.
It's basically going to be an S&M comedy vid. Here's the lyrics so you can see what I'm talking about. Basically, I have them trying to completely dominate and break down the other, forcing them to be theirs. Including their alter-egos, which I kinda have representing a piece of their innocence. Though the main appearence of Girl Type Ranma or P-chan would show up during the "Lies, Lies, Lies" part. Since we all know that innocence is all a lie. So no, girl Ranma would not be like a seperate character. She would just be used as an extension of Ranma. (As would P-chan.)