I've translated Moonshell2 beta 5 into italian, hoping there are some italians in this forum Simply replace the file "moonshl2/language/messages.003" with the downloaded file.
I don't have a wii u anymore to test it myself, but if homebrews are not visible on the wii u menu I think you can press L + R + minus to open the plugin menu, there should be an option called "homebrews on wii u menu" or something similar