as a follow up, we are a couple with 2 young kids

I would keep Staff bedroom #1 and turn into a guest suite by relocating the door in the hall next to your basement stairway, then you can open the existing hallway to the bathroom which would create the suite.

Staff bedroom #2 perhaps make a den/office and open the other den to the kitchen, creating a larger kitchen and access to screened porch, maybe with a set of french doors?
Then that space could become the new dining area.

Do you need a formal dining space? If so, perhaps the hall space could be used as a butler's pantry, if not, then I would open that area to the kitchen as well and create a large family living space. You don't show a doorway to the current living room, but I would use large french doors there also, ones with glass, so that space could be closed off and more private when entertaining.

Just some ideas, you know your needs and how you will use the space.

It would be helpful to know what is outside the house - orientation? yard?

Is the garage truly OVER the staff bedrooms? How does that work with the windows? Where's the driveway? Or is the garage UNDER the bedrooms?

If it's over the bedrooms I would be very hesitant to take out any walls in that area (e.g., the one between the two bedrooms) for fear of a falling Camaro.

You could take out the wall between the den and the hall,as long as it's not load-bearing, to make the den larger. In a non-staff household you really don't need that hallway.