can someone who professes their faith, who lives the faith, has been baptized, has partaken of not just the Sacraments, but also the Divine Nature- can this persons soul still be in danger after they die? Can all of the saving- body, mind, and soul, be for nought (I'm not talking here of once saved always saved... at least I don't think I am) and somehow after someone dies they can still blow it?
The thing is, only God knows the heart of a human being - we do not. So, it's probably just not possible to make the conclusion that so-and-so REALLY "lived the faith." And that's probably the reason why Orthodox generally believe that something happens with the soul of a person who just died. Maybe not universally, but in some instances - definitely. If something of the "old man" (Eph. 4:22) still remains there, in the soul of the departed, if there are some passions that he/she never conquered, if there are some sins that he/she never repented of - then there will be some trials for this soul, something that in Slavic languages is called "mytarstva," a series of events when forces of good and forces of evil wrestle for this poor soul; and that causes the soul a lot of distress and suffering. For the soul itself, it's already too late to do anything to alleviate these sufferings; yet, they can be alleviated through intercessions of the Theotokos and of the saints. That's why we pray for the souls of the departed and ask the saints to pray to the Lord with us and for us.