Who are the 'wild men'?

[Kuruharan]

by whom they had been harried and persecuted as long as they could remember

Apparently the Dunlendings were the people that nobody liked.

It is said here that the native people of Enedwaith, fleeing from the devastations of the Numenoreans along the course of the Gwathlo, did not cross the Isen nor take refuge in the great promontory between Isen and Lefnui that formed the north arm of the Bay of Belfalas, because of the 'Pukel-men,' who were a secret and fell people, tireless and silent hunters, using poisoned darts. They said that they had always been there, and had formerly lived also in the White Mountains. In ages past they had paid no heed to the Great Dark One (Morgoth), nor did they later ally themselves with Sauron; for they hated all invaders from the East. From the East, they said, had come the tall Men who drove them from the White Mountains, and they were wicked at heart.~Unfinished Tales: The Druedain

This passage has always caused me more confusion than anything else.

The Pukel-men are presumably not the people whom we refer to as the Men of the Mountains/Oathbreakers/the Dead. (I might be wrong about this...another point for discussion?)

So the tall men from the East would, in this case, be the Men of the Mountains/Dunlendings who were wicked at heart. In this case the Dunlendings were invaders as well in their own right.

But then who are the natives of Enedwaith? For some reason I think of them as being related to the Dunlendings.

[Inziladun]

Originally Posted by Kuruharan

The Pukel-men are presumably not the people whom we refer to as the Men of the Mountains/Oathbreakers/the Dead. (I might be wrong about this...another point for discussion?)

No, they were Drúedain like Ghân-buri-Ghân.

Originally Posted by Kuruharan

So the tall men from the East would, in this case, be the Men of the Mountains/Dunlendings who were wicked at heart. In this case the Dunlendings were invaders as well in their own right.

The forerunners of the Dunlendings, maybe. The UT chapter on the Drúedain states:

An emigrant branch of the Drúedain accompanied the folk of Haleth at the end of the First Age, and dwelt in the Forest [of Brethil] with them. But most of them had remained in the White Mountains, in spite of their persecution by later-arrived Men, who had relapsed into the service of the Dark.

Those 'relapsers' were seemingly the Dead Men of Dunharrow. Interesting that they rooted out the 'native' Drûgs, and their later kin complained of being similarly treated by Gondor and the Rohirrim.

Originally Posted by Kuruharan

But then who are the natives of Enedwaith? For some reason I think of them as being related to the Dunlendings.

UT also makes mention (The History of Galadriel and Celeborn) of Men living in Enedwaith. We know that there were already Men in Eriador who made contact with the Númenóreans when the latter returned to Middle-earth, and those were said to be of the same stock as the Edain who had crossed the Ered Luin in the First Age into Beleriand.
It was later, after the time of King Aldarion, that the inhabitants of Enedwaith (presumably those same peoples who had met the Núemenórean voyagers before) that became hostile because of the Ship-men's timber-cutting. The Númenóreans then started treating them as enemies.