Since you have multiple houses, you can buy cylinders of it on ebay, if you think supplying it yourself to the technician will be cheaper overall. 

Additionally those that can wait it out should have supply and demand on their side as many VR owners have already converted to LTRs thus reducing the supply once the flood gates open.

The demand seems to be higher than the supply = rising prices.

There will be costs even if your "tenant" is supplying the tiny house. 

Many retail stores and services are seeing a sharp decline in demand or are totally closed, while others are adapting customer experiences and distribution channels to conform to new norms around social distancing, and a few are capitalizing on emergent needs, such as for consumer staples like packaged food, household cleaners, medication and home office supplies.

This past track recordM along with future indicators (vacancy, population growth, quality and diversity of jobs, supply, etc.), places the investment as perceived low risk and high return.  

When doing a top-down market analysis, you want to look at fundamental supply and demand characteristics: healthy and growing population base, demographic trends, diversified employment sectors (so if one industry goes down–like the auto industry in Detroit–the whole town doesn't go down with it), talented and educated workforce.

3)Did lenders supply a loan for rehab to take place or was this something saved for?

If it had a refrigerator when they rented it, then yes, you are responsible for supplying the refrigerator.

From my understanding, if the landlord wishes to deduct any amount from a security deposit after a tenant moves out, the landlord must provide an itemized return letter with receipts for each reported issue.If a majority of the repairs/cleaning was completed by the landlord, how can you provide a receipt for the work (assuming the landlord had all needed supplies on hand to complete the work)?