You would basically offer the same set up utilities but you would have a residual income monthly by renting the plot to the owners of the space. 

Generally - the depreciation on the structure, mortgage interest, property taxes, repairs & maintenance, insurance, property manager, utilities, vehicle expenses (mileage), professional fees (reports/CPA), home office (office supplies, percentage of utilities, continuing education).

My husband and I currently have a rental home in CA and want to utilize a 1031 exchange to build an ADU on an existing, non primary residence in FL.The existing Florida home is co-owned with our son, and this is currently HIS primary residence, not ours. 

I can pay utilities, insurance, and other holding fees but I won't have enough to pay other cost like listed above.

Electric heat can be very expensive in the winter so I would always encourage landlords to have tenants pay utilities so they have some incentive to conserve.

Life changes made it necessary to find a new living arrangement and if I'm going to move then why not buy and utilize financing for owner occupied multiplex?

I spent 2.5 years getting all the utilities to the property.

Utilized a low down payment loan, maxed seller credit, tax proration and closed on the 1st of the month to maximize my cash and acquire this property What was the outcome?

A realtor who used to have a PM company called "JBS Realty" until this month.He used to manage 8 of my properties and is currently refusing to pay out multiple 5-figures worth of rents/property reserves/security deposits/unpaid utility bills owed. 

A lot of lenders used to apply 35% for expenses, but in the last several years, the numbers for supplies, labor, utilities, taxes, etc… have increased significantly.Also take into account the age, occupancy and how has the property been maintained, this will affect the expenses too