Wikia will not allow wikis from Wikia to merge with external wikis. They do not offer any help with it at all. I know as I have asked about it in the past.
It is good that you never gave in to Angela. She, along with the other staff, have ruined Wikia with the new skin. I only work on two wikis now, an answers wiki, UnAnswers, that is a joke answers site and Fable wiki. I still work at Fable as I tried to get the community to move but it didn't happen.
As of now, I have moved my other major wiki, Wikisimpsons, to ShoutWiki. I thought about self hosting but I am still young and don't have the money to host a wiki.
Whoops, I appear to have gone off topic a bit. Anyway, Wikia sickens me. They caused a lot of controversy with the buying of Uncyclopedia. I really wish that they never gave in. Just happy to see you hold up and not give in.