@Joel Wilmoth  agreed.. our little turn key review site were folks can leave comments and reviews gets about 2,000 hits and distinct uses a month.. and many on that site have never heard of BP..

From your pictures, it doesn't seem like anything is in immediate danger, and like Marcus pointed out an engineer is going to recommend you bring the entire house up to code, which I guess would entail new footings, columns, and beams. 

Or perhaps obtain distinct financing for each project, like a renovation loan for the maintenance tasks, an owner-occupied loan for the ADU, and an investment or primary home loan for my daughter's property?

I am still getting to grips with the buy to let issue tax wise but my understanding is if you are domiciled in the UK, a US property using mortgage finance and not in an LLC gets dragged into the UK tax code which can be dangerous for high earners

-Well the deal you think you found under 400K more than likely needs a 100K+ renovation...if not then the house is in a dangerous area.

That said, the exemption when located within a ½ mile of a public transit space is a critical distinction that opens up your opportunities. 

Some operate with dangerously low staffing levels.

There's no distinction between the two that I can find.

Without having professional advice on this front, you are putting yourself in a financially dangerous situation.Also, this seems a fairly complex structure. 

You are right, I have intermixed the two distinct differences between REPS and STR loophole and apologies for confusion.