This was common enough - especially in Andalusia. They basically met the same fate as the Berbers after the fall of Granada. Just like the Berbers, the Jews that were not immidiately kicked out were allowed to stay if they converted to Catholicism, but they were constantly harassed by the Inquisition, and were eventually expelled anyway. It is safe to say that people of part Jewish ancestry had it even worse than people of part Berber ancestry. The Greeks are the least important of this group - as they were too few in numbers, and did not come with any intentions of settling the land, aside from a few trading posts along the mediterranean.
Greek ancestry is very unlikely.
I'd say that most Spaniards are basically a mixture of Iberians, Celts, Romans, and Germanics. Although many Andalusians and southern Spaniards may have some moorish blood. Hmmm, this is a tough one. Even so, by VIII century Visigothics could be considered Spanish and not invaders any more. Actually, it is believed that it was closer to 200,000.