1. Salaries -- have you taken a look at Josef Ka's salary calculator? If you download it and play around with it a bit you get a decent idea of how increases are likely to happen. I agree with Wally that the difference at PF is probably not that much. Once a player gets the higher skill levels, even a one-level increase in a couple of core skills sends his salary up exponentially.
2. Strong inside ratings -- a combination of solid SF and C play, along with his superior PG, probably accounts for this. I notice when I play my better PG, especially with PTB, I get a lot of good shots inside and my opponents' ratings dip. But my good PG is also my best SG so I don't do that much.
3. Best player with a 3.0 rating -- sure, you played him at SG and their SGs went to town on him. If he did a lousy job defensively that would be reflected in his rating too.
Plus in the June 16th game, you held out a couple of your better players, didn't up your effort, and hardly had any contribution off the bench. The fact that you won is a tribute to the balance of your team. Although I am a little surprised that you're struggling if the situation in your league is as you describe, since your team looks pretty good.