Can someone guide me where to apply and obtain a license to build this basement unit to an official unit with its address, electric, and other amenities?

However, getting a policy to cover a few thousand dollars worth of damage to one of my glamping tents is not worth the money, time, or energy for me.

Older buildings with older systems: plumbing, electric, HVAC, roof, tend to have more maintenance costs than newer properties.  

Mainly because I "assumed" how long could utilities such as water ,trash and electric really get backed up without getting shut off.

Mitigation Strategy: Cost-efficiency improvements such as energy-saving upgrades or negotiating better service contracts to reduce operating expenses.

It has separately metered electric service. 

You can also consider increasing your deductible to lower the premium, assuming you have enough reserves for emergencies.Energy Efficiency Improvements→ If you cover utilities for your rental properties, look into energy-efficient upgrades (such as LED lighting, better insulation, or energy-efficient appliances).

Units are metered separately for gas and electric.

Rick, I think online permits are limited to the items below that I pulled off the website: Request Electrical & Plumbing permit for new or replacement electrical & plumbing for single family/duplex homes

I did everything myself from cabinetry, drywall, flooring, windows, plumbing electrical, etc...