For the 1st and 3rd dresses, I suggest more photos. Two are stock and the others are insufficient for authentication. Ask for full length photos (to count bands), all tags (clear and close up) and hanging straps.
The second dress checks out for band count where fake dresses are obvious.
I am not the most knowledable in HL but I checked for what I know to look for and this is my advice. Hopefully others can chime in to give a more definitive answer.
I desperately want it to be real but I see some red flags:
1. There are three of the same tops posted and in different sizes
2. There are 3 "reina" dresses posted in the same print
3. I have never seen the Gingko print in anything but a wrap and the reina style
4. I cannot find a picture of the top on any of the archive top retailer sites
Listing says size XL but tag shows size L. Probably using stolen photos. Wouldn't trust the seller. There's simply way too many fake Givenchy shirts on eBay. This unfortunately, is probably another. It's such a classic shirt IMO and it's really too bad that the fakes have ruined it. The fakes have probably driven up the price for the real ones too, because it's SO hard to find an authentic now.