To be fair, most championship teams in NBA history have had at least one high-usage guy (maybe not 30%+, but fairly high). The one superstar, one/two quasi-star(s) + roleplayers model has been the best way to win titles. It would be kinda unrealistic if you could easily win a title in this sim without at least a 25% guy (the only one I can think of that came close was the 2004 Pistons team... and Rip was at 25.7%, I just checked, and he had Rasheed and Chauncey helping out with the scoring. Also, another weird thing with that year - Kevin Garnett had the most points scored for the season, apparently, although TMac scored more per game). So, it isn't that weird that odd things happen when people put together a team without enough usage - you can't expect players to put up their real-life stats in that situation. SOMEONE has to take the shots (and probably miss them, since they're likely forcing more difficult shots than in real life).
And Fat Lever taking 29 shots in one game doesn't seem crazy. He took 16.7 shots per game in real life. Do you expect him to take exactly 16-17 every game? In real life in 1987, Fat Lever took 24+ shots in four games (he never took 29), and that was on a real life team with Alex English (29.2% usage). So, for him to take in the high-twenties on your team every once in a while doesn't seem crazy to me. Players are going to react to the other players on your team, they won't just replicate their real life stats.
As for why you were shooting so many 3s... maybe it has to do with your opponents' defense. You don't seem to have any crazy perimeter threats on that team (as evidenced by your low # of 3PA), so maybe your opponents are all playing you at -2, which causes you to take more 3PA, as you can see at the below link:
http://www.whatifsports.com/knowledgebase/KB_Article_Details.aspx?kbid=702