watch the first episode and toi find that the G is just that G he was never donné a full name he was born and the just gave him an initial, he is an orphan and all he was donné was the letter G. I believe this will be a running part of the story all season.
I don't know. Since in the season finales on "original" NCIS, really big things happen, (main characters getting killed, main characters leaving the team, etc.) I'm guessing/hoping that during the season finale of this season, they might reveal what the "G" stands for.
Well as a young child he was living in Romania (Evident in the season 2 finale) so i dont really think the name would be english/american origin, but if it did, my mom thinks George, i Think Gregory ou Graham :L