Then you have airlocks, corroded air purge valves & the replacing of $118 solenoid valves.

This determination is highly factual and strict documentation requirements exist to prevent abuse.

Last, is the amount you have to pay a deal breaker preventing you from achieving income goals and/or makes it worse than a property without the Mello?

Maybe sweep a bit first, add an air freshener and a pretty looking plant at the top of the stairs (check with your staging guru on this one though) 

Here are some ways to increase cash flow from your properties:1.Raise rent: Regularly reviewing and increasing rent can help increase cash flow from your properties, but it’s important to ensure that the rent remains competitive and in line with the local market.2.Improve property management: Hiring a professional property management company can help streamline operations and increase efficiency, freeing up more cash flow.3.Increase occupancy rates: Increasing occupancy rates through effective marketing and tenant retention strategies can increase cash flow by reducing the amount of time the property is vacant.4.Implement energy-efficient upgrades: Making energy-efficient upgrades, such as installing energy-saving appliances or adding insulation, can help reduce utility costs and increase cash flow.5.Implement a preventative maintenance program: Regularly maintaining and repairing properties can help reduce the costs of major repairs down the road and increase cash flow.6.Diversify your portfolio: Diversifying your portfolio by investing in multiple properties in different geographic locations and markets can help reduce risk and increase cash flow.7.Refinance: Refinancing your properties can help lower your monthly mortgage payments, freeing up cash flow for other expenses or investments.By implementing these strategies, you can increase the cash flow from your properties and achieve a higher return on your investment.

if you're going electric I don't think you can beat these....probably 1/4 what it cost to run baseboards.and you have air conditioning too!

It was common in some countries to open windows for fresh air even in winter. 

The fact that we literally provide one of the most important commodities outside of like, nutrition and air!

If you insist on one of the options above I would go with option 1 and continue to enjoy the air bnb cash flow and allow the equity to grow more. 

I often break it down into the "five pillars" of protecting your assets.1st pillar is avoiding unnecessary and risky activities (don't drink and drive, insurance generally won’t cover your poor decisions) and take good care of your investments - these simple steps will help you prevent lawsuits before they even occur.2nd pillar is a good insurance policy as that cover the majority of your exposure.