New job-titles

Tiotalan-obrach ùra

We met several job titles with the word  neach  in them in the last section. What happens to them when there is more than one?

luchd-smàlaidh
firefighters
luchd-leasachaidh
developers
luchd-aithris
reporters
luchd-sgrùdaidh
inspectors
luchd-reic
salespeople