Thanks for reminding me of my manners,
G55. Welcome to the Downs,
Marhwini! Help yourself to a skullful of cobwebs and condensed mist and enjoy beingd dead.
Looking at your list of marginalized Mannish peoples of the East and South I feel it's a pity that they were all relegated to the status of tools of the Enemy, it would have been interesting to learn more about their culture and history (although, to be fair, Professor Tolkien already gave us more than one man's share of worldbuilding, and to ask for more seems a bit greedy) - but on the bright side that leaves us so much freedom to invent stuff for fan fiction and RPGs.
I'd like to add the people of Dorwinion to your list, of whom we know little more than that they made very good wine and were for a while subjects of Gondor. They were probably related to the Woodmen of Rhovanion and the Northmen of Dale, but given the geographical position of their country it seems reasonable to assume that they had some admixture of Easterling blood (or at least that was the assumption I made when playing a Dorwinian character with a faux-Slavic accent in an RPG in days of yore
).
Aerin! Yes, Aerin was a bloody great character. Also Andróg, the outlaw in Túrin's gang, and Mîm the Dwarf (but he's not really minor, is he?) and of course Sador Labadal whom I forgot to mention up there although he's really one of my favourite minor characters in all of Tolkien. The Narn is full of interesting characters, isn't it?