Re: wiki recommendations
It really depends on what you want to do with the wiki. If it’s going to be a workspace for individual members or BP groups, I would recommend something like https://wordpress.org/extend/plugins/bp-wiki/, or the new plugin that I’m building with @dwenaus https://github.com/boonebgorges/buddypress-docs
If you want your wiki to be more along the lines of Wikipedia – a shared knowledge base, visible to all members of the site as well as the public – then MediaWiki is pretty good, but it’s a bear to integrate and keep integrated. You might accomplish something similar by setting up a blog on your MS installation as the ‘wiki blog’ and then enabling a plugin like http://wp-wiki.org/