The only reason gold, sand dollars, or glass beads ever had any value is because they could be exchanged for something useful.

Could I be added to her insurance somehow? 

A contingency should be added to the purchase contract or lease that allows the buyer/renter to have the property tested for lead paint at the buyers/renters cost before purchase or lease is finalized.

So much sqft be added, does the seller need to get the permission from county?

Depreciation from personally owned vehicle miles driven can be added back to your taxable number, to bring you closer to your true net number. 

This increase may be added to the rent and security deposit.

Multiple containers can be added to make bigger units so they don't have to be just ADUs but main houses - for example use 3 to get roughly 1100 sqft.So apart from the time frame saving (say 3 months instead of 9 months), there is moderate cost saving over even the cheapest stick frame one can find in Austin.

But their electrical will be added to your bill.

Thus today I will be going to Lowes to get some 4' x 8' bead board panels to match a house I'm working on.Also, regarding local yards, I'm doing a major project in a town that doesn't have Lowes or HD but has a local yard literally 3 minutes drive from my project.

If the prices are right, two more properties will be added to my portfolio by the end of the month.