with maybe the exception of a parcel that is clearly served by city Sewer Water and have power and Tele / internet to the lot lines.. and you have double checked the hook up or Systems development charges and if they have capacity.. keep in mind many parcels in subdivisions that were basically built as recreational subdivisions decades ago.. ( think GLEN GARY GLEN ROSS and for sure watch that Movie is exactly how the industry was in those days) the original infrastructure was allowed to be built to maybe serve 20% of the development that was legal and now you have moratoriums and assessments etc etc..

New flooring, new cabinets, new tankless water heaters in 3 of the 4 units.

Also, if the tenets already pay for their own electric and gas can you use RUBS (if leagal) for water and sewer?

In my experience, many insurers will cover the house but not the roof, ensuring you have protection against fires, broken water pipes, falling down the stairs, etc.

Couldn't get the water turned back on without an inspection.

The cabinet under the sink had water damage to the base, and I have the option of just repairing that and painting the inside of it.

The more you can put down typically the better. you also though want to make sure you have enough money in reserves for rainy day - such as a hot water heater breaks or something.

Quote from @Bryan Waters: I love the ADU play. 

As someone who lived in Satellite (behind the CVS beachside), I will say the upkeep with the salt water was tough, but the area was phenomenal. 

You are not required to pay upfront costs (and shouldn't, in my opinion.)I require written verification from utility companies (water, gas, electric) that utilities have been assigned to Tenant effective the first day of occupancy; no confirmation = no keys and lease approval withdrawn).