For a 10 story parking structure (2-stories underground) founded on drilled piers, I am recommending the use of a single line of drilled piers under the retaining wall and column pilasters in order to prevent differential settlement.
Drilled piles are commonly used for deep foundations, so I don't know specifically why you are asking. Use the drilled pile solution under the whole structure.
For a piled foundation under retaining walls I have typically seen it detailed with two rows of piles under the retaining wall (a concern for rotation I believe). I didn't think an additional row of foundations is appropriate and the rotational concern can be ruled out.