There's a few ways of going about translation...
Super Mario 64's script is compressed and requires a tool to edit/reinsert the edited text, a tool was released just a few days ago to help with this, however afaik it only supports the (U) version of Mario.
Wave Race I haven't looked at in that way, I imagine all the menu's etc are stored as seperate images, I've no idea if they are compressed though. If you look at the rom using a tool called 'Tile Molester' it should let you view some of the games graphics if you can get the right format showing, and if they arent compressed.
There's always the 'texture replacement' option in some of the graphics plugins, though thats the easy and boring way =P but it'd probably be more than enough for what you want to do

Feel free to msg me if you want help doing it via editing the rom, I've 'studied' a few n64 roms so might be able to help a little if you need
