The Mavericks aren't the big challenge to the Lakers repeating next year, the Kings are.
The Mavericks don't have anyone in the middle, which was their achilles heel against the Kings. If the Kings can manhandle the Mavericks with just Vlade in the middle, what do you think the Lakers will do with Shaq?
As for the Mavericks getting either Oly or Zo, I'll have to look into their ability to do that...I would imagine they are already WAY over the cap, but I'll look into it.