One thing to note is that my sister-in-law has not reported the physical abuse to anyone other than may wife (as of last night) as she has been afraid to tell anyone. 

Including the physical work.  

This would be my first ever flip, thousands of miles away, with no way for me to physically be able to help/do anything.

My absolute best advice when it comes to managing a remote construction project in which an owner or investor cannot consistently be physically present is to not do it.

Also, in most countries, it's the physical residency that provides advantages rather than the nationality.

Some have said that because these are accessory units not physically connected to the existing building that I can (i) maintain my current residential financing and (ii) I should not need to use commercial financing should I wish to refi/ a future buyer should be able to get a conventional mortgage. 

Not only does everyone hate moving appliances, but it's very probable that any individuals looking to rent in that area/price range do not have the physical or financial ability to get their own appliances.

But, no one has any "legal" ownership of it, and no one has the physical title in hand.

Foundations, major mechanicals, and sewers to name a few big ticket physical items to look for.

Are you implementing two leases because of the physical structure of the home?