I tried three different times with finally settling with Orlando. Use Dwight Howard for almost everything. He can block almost everything and dunk without being blocked like everyone else.
When it comes to the Boss Battles there are easy ones and then some tough ones.
Kobe, Wade, James, Paul, Bird (dont let him get hot), and Dr. J.
Shaq- Get the ball and score, after scoring, go to the top of the key. Once there run back and forth. When Shaq tries to shove, avoid it and score with ease. Continue till the time runs out.
Magic Johnson- With Dwight Howard, stand under the basket and try to block his shots as Magic teleports
Yao- Same way that you use to beat Shaq. Just make sure when "M" shows upthat you grab it. It makes Yao small and keeps him from blocking your shots,
Karl Malone- He shoves like crazy so for this one, I took Rashard Lewis. Lewis is quick and can shoot 3 pointers. Same method as with Shaq, but score 3 quick dunks. Then you are on fire so shoot threes all day to win.
I hope this helps. These guys are annoying to face and beating them takes time. I did it this way so if you follow I hope it helps.