Bank statement or letter head from a bank stating you have "xxxx" funds available.For financing you will use a pre approval letter.The distinction needs to be clear because of the financing contingency and how your offer stacks up against other offers.

Now a few miles away on the other side of town there were houses built in the same period that were small 1000 sqft cookie cutter boxes and the area was C- to C at best with a distinct lean towards D in some areas.

That is an important distinction. 

If there is a distinct chance that you will hold this property long term, lock in generationally low rates now.

Landlords are not required to issue them unless it is their distinct trade/business.

You're just adding extra layers and complication at this point.If you are actively looking for other PM clients, then a LLC makes sense for that distinct company.

My questions are:  1.) what causes this distinct "old" smell?

The distinct advantage is that it allows one to avoid the dredded issue of holding title for 90 days before reselling.

Makes an important distinction as I like to think of an exchange as kicking the ball down the road and that is the reason they are not heavily audited.

You could try it throughout, but I think people like clear distinctions  of rooms, so I wouldn't recommend it.