Nice, good work. Adding classes was something pending on my todo list. Glad you made it real and that there are still people making plugins for Half-Life
By the way, I'm seeing that the class names are not being translated, Is it intended? In any case, you need to modify zx.txt which is located in addons/amxmodx/data/lang. There are examples on how I use multilingual in the source code, not sure about menus though.
It would be nice to see a video showcasing the classes and I'm looking forward to zombie classes too ;)