Since this morning I've probably watched an hour of this stream all together. I've seen them encounter one person while questing, a Warlock of the same faction...he killed some named quest mob about 5 seconds before they got there...they were pretty pissed, lol.
To answer your other question, the two of them have played as a duo the whole time I've watched. No guild help or really any interaction with others at all.
OP stated they chose Hunter/Warlock for the ease of leveling with each class. -- McBrain#1430