1a - Your team averages a pretty high 20.4 fouls per game, so it seems your team is prone to fouling. You had 3 guys foul out and according to their stats they seem they are pretty aggressive players.
1b - From what I've seen, nothing scientific of course, but it seems clear that teams that have to defend look inside foul alot. Basically, they just bowl their way into the paint and get fouls. IMHO this is an area the game engine could use some adjustment.
1c - Maybe some of those fouls were racked up during the last minute?
2 - Guards can still score a lot playing look inside/low post, they just do more of it in the paint then outside. A quick glance a the shot distribution seems to indicate most of his points were score in or near the paint.
3 - First, the trainer wouldn't have any effect on substitutions, and there's not a staff member that you can hire/fire that would. It's the same virtual coach for all the teams. Hard to say why the better players wouldn't be subbed in, only the BB's could take that one.