The semi retired missions are available a lot earlier that L65. Wasteland (Nimbus) is available to Fed characters at least 5 levels before the actual level the world map is scaled to. I deliberately ran it on my recent Fed Delta Recruit before doing the Reman Arc.
The rest seem to unlock at or near L50.
Comments
Are you referring to the "Incoming Hails" tab? If so then it's not available for new character I made.
https://sto.fandom.com/wiki/Breen_Confederacy
Then search for them in Available tab once your 65, as others have stated.
The rest seem to unlock at or near L50.