Would you consider an engineered floor? I'm no expert but you might be able to have a floating floor installed in which case I think you'd eliminate the need for sleepers unless the floor is horribly uneven. I think the manufacturers suggest specific vapor barriers for their particular product and you might even be able to use some kind of padded underlayment for some insulation?

Unfortunately, the rooms that need new wood floors abut a hallway that is tiled. The height of the wood floors has to match the height of the tiled floor, and they won't without using sleepers.