Hmm. This is definitely an interesting idea. I'm glad you're changing Magikarp's moveset though; it would be the most infuriating hack on the planet otherwise.
I like the idea of you using the images of Magikarp/Gyarados from the 2nd banner in your sig as well. That would definitely set them apart from your average Magikarp.
In terms of Magi's stats being increased, that's a good idea for a lot of reasons; especially for when it evolves. I've always found Gyarados to be distinctly average, maybe a little bit above at best. It will be nice to have one with better stats and possible move pool. I wish you the best of luck with finishing it