Assuming your question was about adding that picture in place of the Minnie, I added it for you. I don't really know about current NT players, so I don't know how much I would be able to help out with that wiki. ¯\_(ツ)_/¯
You should ask FANDOM to enable Gadgets on the wiki, because you can do all sorts of things with them, like change the appearance of the wiki for you only, get extra tools to help with editing and moderating, etc.
Gadgets would have to be enabled tho. You have to ask FANDOM to enable them. You activate/deactivate them in your preferences. You can see them in effect at the MooMoo.io Wiki (I Lead that Wiki). You don't need to care about the content, but you can see examples of gadgets in use.
OK, though I don't see why that is necessary seeing as to activate them, you hover over your profile pic (on the top bar next to the search bar), go to Preferences, then the Gadgets tab and a menu like this should appear.
There are cars that have multiple skins. The admins just haven't made them available, but they have shown them in random news posts. When skins come, which will be soon™️, will the template just be updated?