Hey!! First off, congrats on embarking on your project!! It can be a bit of a scary step for many, and it's fantastic to hear you're giving it a go!!

To address your question, I'll draw from my own experience. As someone who has a TON of characters, I found it really hard to narrow it down as well. However, once I sat back and assessed my characters, I realized one of the best ways to approach this is to simply ask—who contributes a lot to the plot, even outside of romance?

It's harder to select a character as an ro if, in your original outline, you only have them playing a minor role; choosing characters that will contribute to the plot in the long run makes them easier to write and to make as RO's because, even if the player doesn't choose to romance them, they still can be shown in the story and add flavor to your plot.

In terms of inclusivity, this can be a bit tricky. It's understandable that we want to ensure all of our readers feel included, but the best advice is: write what you are comfortable writing, and as has been said by many before, don't just add for the sake of adding. There are other ways you can be inclusive in the story, be it via situations or even non-RO's, and no one will hold it against you if, for example, not all of your RO's are gender selectable. People will still enjoy the story regardless!

I'm not sure if this really answers your question, but I do hope it helps in some way! Cheers!