Hi Andrew and congrats on making the best decision of your life. As mentioned above - are you going for Hero or Stunt? You will need to make some modifications to the helmet if you are going for Hero.
Mark does indeed include a green lens in his kit (flat - stunt version). Although screen accurate, I find that lens a bit too transparent - people can see your eyes in pictures. I opted for a darker lens as provided by Mike at Trooperbay.com. Any dark green welding lens would work too - unless you are going for Hero, then you need to source curved lenses.
The AP kit does include a lot of the little extras (split rivets, any visible snaps, frown mesh, screws for the helmet and ears, etc). As for a neck seal, I used Geeky Pink (Teresa or "Soulart" here on the forums).
You'll want to get more magnets.
Good luck on the build!