FELT PRETTY MUCH COVERED IT.
As far as US goes with fields I wouldn’t worry about it unless your actually using footage, In Ae you will want to interpolate your footage if it is interlaced. I always use DG fastchannel (digital satelitte delivery) I encode an MPEG2 based off of their settings. If i remember correctly its upper field first but it shouldn’t matter what the source is before MPEG compression. Most of what I do lately is HD so it all square pixels. I havent dealt to much with SD now a days unless we down convert to SD, which I just do on export by either center cut cropping the HD or letterboxing it in SD. Hope this isnt to confusing as it always is.
B