Also remember it will take time to get them done, during which the home is vacant and not on the market.People shop with their eyes-so many don't care about stuff that is really important (plumbing, electrical, roof, etc). 

Wildfire risk is also nearly non-existent close to the coast, and haven't yet heard of hurricanes or tornadoes, but you will notice a tsunami sign or two..Electricity, water and general operating costs are surprisingly 'affordable.'

New mechanicals (HVAC, electric, plumbing), kitchen, bathroom, adding a 1/2 bath in basement or 1st floor, new drywall, floors, paint, etc.

The most pressing, and i cant seem to find a true answer from the the building department OR the utility companies is if I need to have separate meters (Electrical, gas, water) for my ADU and main home. 

The problem that I'm thinking that we will run into is that water and electric will be difficult or impossible to have routed out there.

However, one recent sale in the area was 109K for a .15 acre lot, however, it was verified developable and had gas, electric, and water at the street.

Insulate, add electrical, mini-split ac, and possibly plumbing, as desired, drywall, tape and paint, put built-in cab's on one side if you want, hang the tv, speakers, etc, install bi-fold/multi-fold doors on the side leading to a patio, and replace the garage door with an insulated one keeping the track and removing the motor, or install a carriage type garage door into the existing garage opening.

4 individual water and electric meters.The point about individual townhomes and sprinklers.

AC, electricity, no plumbing.

During this time, inspect any agreed repairs, inspect all appliances, check whether all doors and windows are secured, working properly, or to your satisfaction, belongings of the seller are completely removed, check for signs of mold, check electricity and outlets, and inspect the exterior & backyard.