Can i say Tvoje oblíbená barva je zlutá?
As an affirmative order question yes, but the English one does not use the affirmative word order (Your favourite colour is yellow?) so I wouldn't use it in the translation either.
But it should be an accepted answer anyway
can you change the word order of barva and oblivena?
Could I have said Je žluta tvoje oblíbená barva?