The story was nice, but... definetely homura and sayaka do not match, it would be a hell of a story if madoka takes sayaka's place
Wait... that was Sayaka...
I read this and did not notice, my brain automatically set up Madoka there, felt weird cuz of the hairstyle but I just did not noticed until I read your comment xD
THAT's the right thing to do, I tell you.
And perhaps this deserves a Spoiler
since it's talking about Rebellion?