Eeeeeep! I am so excited to read this! It's a new direction when it comes to HP fanfic. Though this seems more like an original fiction since I've never read anything about the founders before.
I really like this! It's a really creative and interesting idea. I can't wait to see where you take it! I can never seem to get too much Harry Potter. There were a few flaws. Somewhere in there you spelled defense with a "c" instead of an "s". Also, you mentioned Godric's name before he ever told it to Rowena.
"But just as quickly Godric turned around as if expecting it, drawing his wand to deflect the spell in one quick motion."
I can sort of understand how that happens when you get so wrapped up in your story, but that was about it really :) Overall really interesting and I loved the dialogue the best I think. Witty is the way to go. Haha!