Hmm, anything specific you need help with? You can check Help:Theme designer if you want to upload the background/wordmark or change wiki colors, Help:Navigation if you want to update the navigation bar or Help:Contents if you generally need help pages.
After several days of thinking, i am planning to adopt the fanfiction wiki.Tough choice, but i guess i have to make the most out of the situation.After all, i have the experience of failing to adopt a wiki/taking care of a wiki.I will see what luck has planned in a few days.
I'm not sure what it is either, but I guess Man Son You's link is explaining it. Storyshift is when you take multiple characters and switch their stories around, for example, Storyshift Asriel is a normal Asriel but with Papyrus's attributes, it looks like.
Undertale art book is a product you pay for so adding it whole or adding screenshots of it would probably not be very legal. I'm pretty sure pictures of merchandise from Fangamer are already in galleries.