Thank you! I am Odd, who did Eldritch's wiki. (I also did the non-default wiki skin, Kent, for The Reach, but I've improved a bunch of stuff since then. Yay!) I'm glad people like Eldritch's skin. I put a lot of work into figuring that shit out.
I will try to help answer questions!
MediaWiki is an awful, crazy mess of code; Vector, the default skin, is especially so. All the little bits are hidden under other bits and it makes things like changing a background colour all weird and fiddly. I can help with some Vector things. Basically, I hated Vector so much I taught myself how to make a wiki skin from scratch, because I am crazy. Eldritch Wiki's skin, Gears, isn't a modified version of Vector; it's an entirely different skin.
Character and log templates are a lot easier, since it's just tables code for the most part. I can tweak tables like no tomorrow and I try to make it as easy as possible for others to modify pages/use templates.
Ebla's the one to go to for the really arcane stuff. Ebla did things on TR with wiki code I cannot get my head around.