I got my green card through EB2 but not under national interest waiver. You might find some useful information here on EB2 : - http://www.immihelp.com/gc/employment/greencard.html#EB2 I am not 100% positive about (1),(2),(4) but on (3), when I did my stuff, the only time you needed to be in the US was when you were filing the 485. Infact, I was outside the country for sizable chunks of time during my green card process and had no issues as a result. Hope that helps a bit - you might also want to try www.immigrationportal.com - you can get some good (and free) advice on that site. Good luck!