Actually, the kit was available for purchase, sort of. On the Japanese site there was link to make a reservation for the whole kit, i.e. not just the polo or just the shorts. The scheduled shipment is September.
So,
1) I don't know why they chose this kind of distribution (maybe it'll be a limited production)
2) I don't know about the U.S. website - I didn't see anything about the actual French Open polos (green or white version)
3) I said what the heck and placed a reservation (I have family in Japan)
3a) I actually think the green polo with the green shorts is a pretty awful combo but the green polo with black or white shorts and the green shorts with a different white top will look nice