The only thing that looks suspicious is that you're using the UserLoginForm and UserCreateForm hooks. These hooks are deprecated under AuthManager, so it would be good to move away from using them.
All those hooks do is add an image to the top of the form. This is important as it gives context to where you are logging in.
<div class="watermark"><img src="$1"></div> where $1 is the value of $wgMobileFrontendLogo
If you are deprecating these, you need to provide a new way to add that image. I consider that a blocker to rolling this out.