Money is not an issue with Dana or Fedor. It's the length of the contract, Fedor wants to fight Randy Coutre but Dana doesn't just want him for that one fight he wants him to sign a contract for 4-5 fights. Fedor wants only that fight in the UFC. If Dana signed Fedor for one fight and he destroyed Randy the way he did to Timma Sylvia it would look bad for the UFC.
As for the best in the world everyone has their opinion. Some say Anderson Silva, Georges St. Pierre (my personal favorite fighter), Penn or Emelianenko Fedor.
The Last Emporer is 29-1 and the 1 was due to a cut by Kohsaka who he beat later in PRIDE.
I honestly want to see him fight Barnett, Couture, Arlovski or Gonzaga. The Barnett fight won't happen though cause they're supposedly good friends.