I'm the founder of one of the biggest mandolin groups on Facebook for Mandolin Players. As of this posting (5/31/18), we have over 1,000 members.
I've added two documents to the group's files. The first one is a database I'm building of Luthiers who specialize in Mandolin repair and restoration. The second one is a database of Mandolin Teachers.
If you know of any luthiers or teachers to add to either of these databases, please join the group and include them in the documents.