Do airlines employ FAs from their destination countries?
The 747 carrier I retired out of had FAs based in New York and Tel Aviv, and were residents of their respective countries. The citizenship of the JFK FAs was not a factor insofar as I know as there were numerous green card holders.

Non-stop flights between JFK and Tel Aviv (and return, of course) were staffed by Israeli FAs. All other flights were staffed by JFK FAs. The primary reason for this arrangement was cultural. For JFK/TLV the back quarter or so of the aircraft was allocated to Hasidics to attempt to satisfy their preferences. For example, no movies were shown in the back because they were objectionable to the Hasidics.

The advantage of having Israeli FAs on the direct flights was that they knew how to handle the Hasidics. Scheduling problems would occasionally result in JFK FAs operating a JFK/TLV flight. It was not uncommon on such flights for the cabin crew to request a cockpit crew member to come back to help mediate a dispute. I never received such a request from an Israeli cabin crew.