The only evidence is to refer to the BIG PICTURE.
These nutjobs "know" the Earth is flat, thus everything stating otherwise are evil lies and deceit from the governments.
It's very typical for conspiracy theorists to picture themselves as the valiant few, fighting against an overpowering foe with "unlimited resources" (the GOOOOVERNMEEEEENTS)
Most of the "evidence" comes from blatant refusal of accepting evidence proving otherwise. Pictures of the Earth from the ISS are claimed to be computer generated, without any other reason than "I know the Earth is flat, thus the photos must be fake." Probably the dumbest logical fallacy there is.
Refer to the fact that 400,000 people were involved in the Apollo 11 missions and you hear that "ONLY THE TOP KNEW THE TRUTH!", a desperate attempt to add credibility to a rediculous argument.
1. I suppose it's the easiest way of maintaining the insane theories, with the sun being a spotlight and moon and stars being some kind of discs.
2. By assuming that the FET is true, the answer would be yes. To avoid the fact that millions of competent and educated are involved, the FE's come with the argument I mentioned above.
3. There is none. Again, by assuming FET is true, NASA is involved. Fallacy yet again.
4. There is no evidence for a disc-shaped Earth, but instead there's flawed models which desperately tries to explain midnights and different timezones on a flat disc. It's impossible, but reality is not important.
5. There's probably some creationist undertone in this madness, considering that the Earth is "special" and everything is centered around it. Medieval stupidity.
6. They're simply ignoring it. FE's assume that everyone proposing a round Earth are part of a conspiracy, which also strengthens their false sense of righteousness. Since they see RE evidence as edited, false, bribed, corrupted, they can never be pursuaded otherwise.
I laughed a lot at first too, but after reading the so called arguments of some of the worst here, I can rather taste bile. "The Earth only APPEARS CURVED, HURR DURR!"