1) The "points per 100 shots" measure is a rough estimate of how productive your players were. But it usually doesn't tell much more than the shot percentage of your players (beware that it refers to the subs as well, not just the starters). I don't know how it's calculated, so maybe someone can enlighten us on that. I think I have read somewhere that the FT attempts (how often your player goes to the FT line) is also taken into account.
2) The ratings are overall measures of how well your players have performed. The tactics you use and your opponent also influence it.
3) Your opponent's inside and outside defense were both very poor, so it's hard to read much into it. Your PF and C scored a lot but didn't need too many attempts. Also bear in mind that they also scored 3 pointers (and other jumpshots I'm sure), so they also can take advantage of poor perimeter defense.