Keep in mind that this was done when Florian had yet to release the way to properly do it through ASM.
I'm not an expert in assembly, and have basic knowledge of reverse engineering.
I did this the way I could have done it with what was available and from what I know. So yes, this is a simple redesign of the existing const character selection.
I think you can still use it for EU servers as well... you'll just need to block the region where the character selection is at. Or simply follow Florian's guide to do it properly, he almost gives u a baby step by step to do so anyway.
Also, Thanks for adding the credits
(Something that I think everyone should do when releasing something)