The abondoned story Formendacil is revering to is named "Tal-Elmar" after the name of the mean charachter. In reconsidering the story later, Tolkien sought that he would have to adapt the geography to fit the coast of Gondor some where around later Pelagir.
Since the story breaks of just after the first contact is made, we do not see much of the real Númenorean behavior against the neativs, but we hear very bad storys about them from Tal-Elmars father and the capitain of the ship does says to Tal-Elmar that his people will have to leave since the area will be occupied by a Númenorean settelment.
On the other hand the poeple of Tal-Elmar are clearly under Saurons sway and they are enemys of the Northmann of Rhovanion and the Drûg of White Mountains and the Númenoreans seem to know that (or assumed it as they did wrongfuly with the Dunlandings).
However, the People of Gondor were by the mayorty not of Númenorean stock (look at the trups coming to Minas Tirith in the LotR). It seems that only at the old cities of Pelagir, Umbar and Dol Amroth were greater Númenorean settelments before the arival of Isildur and Anarion. The brother settelt with their people in Ithilien and Anórien, which were as it seems mostly unpopulated before.
Respectfuly
Findegil
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