it can brick your vWii mode (not WiiU) if you install a game with a bad animated banner.
but, it's now possible to edit vWii content directly from the WiiU mode, so if you install a bad wad you can always remove it and get your vWii working again.
if you ever brick vWii by installing a WAD : NEVER guess ! ask for help and WAIT for an answer. guessing is the worst thing you can do and you'll end messing more than fixing it.
If you want, there's another wad manager :
https://github.com/FIX94/Some-YAWMM-Mod/releases
I don't know if modlite has all the fixes and works on AHB or cIOS. So, use wiimodlite or YAWMM-mod, that's up to you. as long as it works.
vWii is limited to 512MB, and 48 titles max.
if you need more space, there are other solutions (emuNAND), but it can be more complicated and less compatible.
the advantage is that it's extra safe, you never install anything to vWii.
if needed, we can later cover it. for now, wad manager is enough.