I am working on my preflop play but have a few questions.

Is isolation the ONLY reason to raise preflop with two unpaired hole cards? Lets say you hold AK on the button and everyone folds to you. Only the blinds are left so you have achieved isolation. Do you raise?

Same question but you hold high PP like AA,KK,QQ. Would you raise because you expect to win the hand and this raise is for value? Would that answer be the same for all high PPs?

Same question for Re-raises. Would you Re-raise someone if isolation is already achieved? Re-raise only with PP?