POST. BOTH. VERSIONS.

That novella-as-a-prequel idea sounds like a great one! But, since you've already posted this, I think you can just excuse it as an alternate version. You can then post a poll to see which version worked best, then the readers can decide which they liked better. This scene was so masterfully written, and knowing that this is your "baby" really makes it stand out. I can feel the passion lifting from the page. Nothing like a labor of love, my friend :D