A couple of answers--
#1-I was/am on an e ticket EWR-LGW.
#2-Upgrading flights to Asia seem to clear immediately with no 30 day window, whereas as stated European flights seem to always wait until at least the 30 day prior to travel to clear. That being said, I've never had a problem getting my upgrade to clear inside that window.
#3-Regarding US Air & upgrades, as a Silver DM attempting to upgrade with certs I've always had to wait for my upgrade to clear at the gate, at time of flight!