Okay, read this and while well written, I can't say I liked it terribly much. I personally always try to avoid fanfictions where established characters play a part. That and the scenario itself just seems unlikely. Even in Housepets, the higher order beings don't spontaneously turn people into other things for reasons beneficial to the person. There would have to be serious strings attached which were not in evidence in this story. Furthermore, the pets have proven to be not terribly accepting of different scenarios and I can't imagine them not at the very least giving Shy trouble for liking not only a guy, but a bat which is a different species.
However these are all criticizations against the person who requested the story, not you. The story itself was fairly good and you managed to pace it well.