I just got Auf Wiedersehen Petrovic trophy !
I can now 100% confirm that
IT IS POSSIBLE TO GET AWP TROPHY IN SEPARATED SESSIONS - but under some "circumstances"
Races - I have won all races playing with the same friend, he was always a host but we did it in like 2 weeks, few sessions few hours each separated by few days of not playing - servers probably had time to synchronise ...(or maybe we even played always on the same server but I do not know if it is possible), also GTA races where last thing I did for the trophy.
Fly the Coop - the same situation - The same friend, the same host, few sessions separated by few days of not playing
BUT MY FRIEND DID NOT GET FTC trophy... (contrary to me he was playing online alot in 2008)
Take it for the team - I did that trophy with random people BUT - when I did it in separated sessions I did not get the trophy so one day I sat and did all team games in one session (quit online twice by accident), I was always a host and I did get the trophy ( Cops and Crooks was the hardest to get due to winning as a cop and crook in the same round requirement) also I had to win Turf War again to get the trophy
I bought the game on Euro release day but almost did not play it until March 2009, I only played one free play game in online mode before July 2009 (right after release), I probably did not get lvl up during that one session.
As for circumstances - that is all I remember - good luck to all who is still trying, maybe my post can help you someway.
From now on I NOOS all the time if there is somebody who is NOOSing too - please contact me.
This post is a crosspost of my own post from other forum (not GTP) but I hope you don't mind.