As you are not in contract, you have no legal obligation to do this.
However, not doing it might well impact on your competitiveness !
From the Client's point of view, they presumably want you to give them these rates so that they can do a comparison with other tenderers.
If, as you say, these costs are already in your fee percentage or other people rates, you can put in very competitive rates. Further, if you win the contract, then when a compensation event occurs involving these people, you are effectively getting double bubble i.e. what is in your fee percentage plus the rate you tendered.