Traditional lending for investors as well as Non-QM for Investor capital with DSCR options as well as 1st Lien HELOCS for investors.

Property taxes are public record and insurance would be specific to you, so you can kill a lot of those questions. 

They argue that tenants wouldn't want to lose their government-supported housing, so they'll be good tenants.

To do this, divide the cost based on the ratio of the fair market value (FMV) of each asset to the total FMV of the entire property at the time of purchase.If you are uncertain about the FMVs of the land and the buildings, you can alternatively allocate the cost based on their assessed values for property tax purposes.Source: IRS Publication 527 (Residential Rental Property)

Generally, SBA loans can only be used directly for real estate purchases if the loan is being used to purchase a facility for a non-real estate investment business that will owner-occupy at least 51% of the property.

Without responding with respect to your zoning and what is allowed locally, I will discuss what is allowed on state level because i believe it will allow what you seek.In 2025 SB 1211 (Skinner) – Multi-Family goes into effect allows an ADU (I think it specifies detached but question if that is a requirement) for each legal non ADU unit up to 8 units.  

Any list you can pull for a few bucks has already been hammered by hordes of investors before you.Not saying this way can't work, but I recommend a different path...I prefer to focus on sellers who have a reason to sell but who require some effort and skill to identify.My favorites are #TiredLandlords, namely owners who have filed an eviction lawsuit against their non-paying tenants.Many of these folks are through being in the rental business and are open to hearing about a way out.Even better, #TiredLandlords are ideal candidates for seller financing, since they don't need the sale proceeds to buy another house, PLUS they are already conditioned to receiving monthly payments over a period of time.

We have products that offers cash out refinance for primary residence or 75-80% for non primary depending on the property type.

But beyond that, your question is so broad, no one can give you advice, other than: go buy a property, or a share in a public REIT.  

You probably think Section 8 sounds easy because the government pays you, but that's not how it is.