The railing at the staircase has to be removed to get certain pieces of furniture down, and I don't want to do that every time there is a turnover.

Nice furniture, maintained, clean, no signs or smells of cats, just pride of rentership.

OR I could build it out to rent the main house and the finished basement (sans kitchen/furniture etc) to one tenant and make my life easier. 

I usually leave a welcome card with things like a 2-pack of HVAC filters, the assorted pack of furniture felt pads so they don't scratch my floors with their furniture, stainless steel spray or special cooktop cleaner if needed so they know I want them to use the recommended product.

., furniture in storage or sold, and then either sell the house or rent it long term.

I think you'd be surprised how much just some basic soft goods like furniture and sofas help with that kind of Noise though, so if both unit are currently vacant I am willing to bet it sounds much worse than when people will actually live there and have curtains and carpets etc.

It's hard to do real work with furniture and personal items in the way.

Stores that have since moved-in to the space include Costco, HomeGoods, Petco, Hobby Lobby, Dick’s Sporting Goods, Field and Stream, Best Buy, and Ashley Furniture Home Store.Transit Oriented/Mix-Use Developments- Mobile Bay Bridge Project is said to begin in 2020, costing $2.1 billion and consisting of a six-lane cable stay bridge over the Mobile Bay connecting Mobile and Eastern Shore.

If it's furnished you can charge more, but you run the risk (in fact I'd say the certainty) of your furniture being damaged.

A few questions:Am I able to expense or depreciate any of the existing furniture?