This sealed off the dust, and gives a grand storage/workshop area,   HOWEVER, it also sealed off the airflow, with the result that any dampness wicking through from the outside soil makes any nearby surface mold heaven.

Against the house I would be concerned about drainage and would want a pan. 

If you simply have several low spots on the roof that have ponding water after it rains in those areas, it can actually be fixed by building up the roof surface in those areas so that there are no low spots.

It would be nice to see a turnkey company offer 100% transperancy on the surface level.

What is the painting tricks for these surfaces as well as smooth walls? 

You will be surprised how much oil/dirt was hidden on the surface in a kitchen.

Assuming the area is pretty flat as shown on your photo you may want to consider sheet vinyl to protect the old tile from surface impacts; it also provides a quick face lift that may help you get a better tenant/rent.

You're not talking about a basement drainage sump pump from groundwater. 2.

Walls & Ceilings & Woodwork & Cabinetry & Every Surface - all will need a good white vinegar/water wash.  

Anytime you are going to do some painting in the kitchen, it's best to go over all the surfaces with some type of degreaser.