Questions and help with wiki plugin

Hello,

I need help about wiki.

First of all i have installed wiki to create a greek political pedia.

I have 1500 wikis atm and the site will have more than 25000-30000 in a while.

I have the wikis widget on a page and it takes 8-9 secs to load the page. How can i deal with this delay?

Also About the new wikis. I want to have the 3 latest wikis appear. I dont know what the levels are and how to handle it. Also i want to have those 3 last appear with featured image an except text and read more button or something like that.

Also how can i change the text of the tabs page, history, edit, advanced, create new.

How can i make a users group on wordpress and that group would be able to add new wiki or edit one?

But also when someone creates a new wiki or edits one i dont want it to be autopublished or autoedited. I want them to be on standby and me as an admin would be able to manually publish it.

Looking forward for your reply