And if they lease new tenants every year you will likely have turnover costs to add as well. 

I just wanted to get a sense of installation cost and permitting process for in ground, semi, or above ground.

Is there any tax strategy that can be used to depreciate the actual cost of the building itself if not used by us for our LLP's business?

You also have a variety of price ranges, lending options, and markets that allow for a low cost to entry. 

A CSLB-issued license is required for all construction-related work that costs $500 or more in combined labor and materials.Thirteen of the 18 suspects were cited for contracting without a license (Business and Professions Code section 7028).

Per my records, I had a loss of ~$30k over ~5 years from management costs, repairs, appliances, etc.

Asking because in most cases, you can pass on the cost of the broker's fee to the tenants or at least agree to split it between tenant & landlord if you find a great tenant and want to incentivize them to sign a lease. 1 - If you still want to self list, you should be able to do it through online sites like Zillow after making an account.

However, I am wary of the maintenance cost and added liability that comes with these amenities. 

Are the costs for pre fab better in your area than a new construction?

The cost of living is extremely low compared to other cities and you can still many many positive cash flowing and 1% deals here.