As to the picture of the young man on the bike, people getting a very dark tan from the summer sun doesn't mean anything other than that the odds are the person is EITHER from Southern Europe or from the Near East. It is possible, however, that the person is actually from north of the Alps. I've said till I'm blue in the face that pigmentation is the least reliable indicator of ethnicity.
I was looking at my wedding album a lot this weekend. This is a picture from it. We were married at the end of the summer when my husband had been working construction outdoors for my father to try to save the money for our backtracking trip through Europe. Now that most of his life is spent in an office, his skin is an olive white.
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The picture of the young man on the skateboard doesn't show the face very well. If you weren't telling me all these pictures are of you, I wouldn't guess.
All of that said, I don't see a family resemblance with any of the family members you posted, particularly not your grandfather's mother, or your mother and her father.
In general, as I said, I defer to the Greeks on the site as to whether you look really Greek to them. I haven't been to every corner of Greece, so I wouldn't know.
For example, there are people like these Greek politicians whom I wouldn't have immediately guessed were Greek.