I would think that greeting games wouldn't count for anything at all--least of all your avg. opp. score. It won't give you a win or loss and it won't raise or lower your overall rating, so I don't think it should. But I don't know. I wouldn't worry about it too much.
Avg. Opp. score question

I would like to point out that last time I checked unrated games on live chess DO affect your average opponent rating. I actually sent in a suggestion about this to the chess.com staff to change it. Not sure if they have yet or when they will.

Phelon, as of two or three days ago, unrated live chess game still affect your average opponent rating and win/loss/draw statistics. I don't care about such statistics, but I agree live chess statistics would be more consistent with correspondence chess statistics if only rated games were taken into account.
This might sound vain, but will the greeting games affect your avg. opp. score? I'm currently trying to raise my score and I'm worried that the ten games I have going on with 1200 rated opponents will slow down that process. I get that it has no effect on your overall rating, just concerned about average opponent score.
Like I said, I realize this sounds petty, but ... does it?