Lagamorph wrote:
I did Arrival after I completed the main story...however I'm wondering if it's going to be worth playing through the end again, otherwise my after-game save might not include progress from Arrival....
Well, just another excuse to do the Suicide Mission again and not lose anybody

I think the import save you use for ME3 is different than what it was like from ME1 to ME2.
I think this time you are actually importing a manual save that has been made anytime after completion of the main story. So it should work fine.