We have not disabled ours or converted to gas, but Tenant must sign a Fireplace Addendum stating if they use it, we require a higher renter's liability policy with us as additional insured, rules on wood, storage, use, safety, they pay for yearly professional cleaning each year they are there, etc.  

Definitely an option in PA, FL you may be limited to 75%.

If one or more units are vacant, the remaining units often don’t provide enough cash flow to cover expenses, making it harder to meet operating costs.Maintenance costs: A fourplex comes with four times the appliances, plumbing, HVAC systems, and other components to maintain, leading to significantly higher repair and maintenance expenses than single-family homes.If you want to see the detailed calculation, read this BP blog - More Units Doesn’t Mean More Money—Why a Single-Family Home Can Beat a Fourplex.Resale value: Multi-family properties have a limited buyer pool—mainly investors—who base their offers on CAP rates.

The LLC is there to protect you from liability when doing business by SEPARATING your business from your personal.

While cash flow can be limited within the downtown area, there are still excellent opportunities for cash-flowing rentals in surrounding regions.

I come across people with limited credit history and/or no score.

Personally I’d do a 1031 to save $40k, I’d skip the LLC, increase the limit on my umbrella, and call it a day.

They could have owned the home for many years and if homesteaded, are limited to up to a 3% increase each year.

I've been researching the topic of limited liability and the different options to achieve this.

I have equity on it and yearly i get around $10000 as rental income but the property is 1989 build and i am assuming that since its very old property the equity gain would be limited.