Eh, I guess I forgot State/FedGov employees who are stationed overseas. I assume they don’t vote through that, so they can be group #3.
4) NO ONE else
It looks like the owner of a couple of apartment complexes may have been part of the theft ring:
https://www.wfsb.com/news/state-to-investigate-voter-fraud-allegations-in-bridgeport/article_4c0c74cc-df0a-11e9-9387-93161f7770c2.html