I've been reading philosophy, and what I find intriguing is the idea that Thales was some wise sage. Predictor of eclipses. Possibly from Babyblonian astronomy. However he is not from mainland Greece. One theory is he might have been from Phoenicia, an ancient group of city states who were known for their sea faring and can hail as far back as 4000BC.
My thought was, if he was Phoenician (a group of city states of which we have limited knowledge of) might have been some highly sophisticated civilization that knew a lot more than Thales. Another theory that seems more accepted is he was Milesian.
Thales was certainly a Milesian Greek. That's not a theory in the colloquial sense of the word; it's simply what the evidence directly and explicitly tells us.
It sounds like you might be reading too much into the fact that Miletos is not within the present-day borders of Greece. In Thales' own time, national borders don't really enter into it; but in terms of the cultural landscape, "Greece" extended much further than its present borders, and included the entire west coast of Anatolia, most of southern Italy and Sicily, and parts of southern France and the southern Ukraine.
Other than Thales' approximate dates and the region in which he and his students flourished (Miletos), his biography is nearly all fiction, so there's not much to be gleaned from it. He is said to have travelled in Egypt, but that's just a romanticised way of saying he had access to knowledge from outside the Greek world (probably including Egypt, but doubtless Babylonian influences too). We have no direct evidence on Near Eastern influences on him, so anything more specific than that is just speculation.
By the way, on eclipses: the evidence that he predicted the eclipse of 585 BCE is very, very poor. The most proximate source on his "prediction" of an eclipse simply states that he calculated within which year a solar eclipse would happen. His actual prediction may have been a bit more specific than that, but the evidence on exactly what it was that he predicted is vague to say the least. There's no good evidence of anyone successfully predicting a solar eclipse prior to about the 3rd-2nd century BCE; crystal-clear evidence doesn't pop up until Han China. (Lunar eclipses are much easier, and were being predicted many centuries earlier.) The coincidence between the Chinese technique and what the Greeks were doing in Ptolemy's time suggests that they may both have been ultimately influenced by Babylonian astronomy of ca. the 5th-4th century BCE or so -- but that's still later than Thales. One relatively recent treatment of Thales' "prediction", D. L. Couprie 2004 "How Thales was able to 'predict' a solar eclipse without the help of alleged wisdom", Early Science and Medicine 9: 321-37, points out a set of coincidences in solar eclipses observable from Miletos in the period 610-585 BCE that suggest he may simply have got lucky.