Additionally, there’s always a risk that any pet-related damages could be hidden under furniture or otherwise concealed, potentially leaving us to cover the costs if the security deposit is fully depleted by other expenses (e.g., damages or unpaid rent).

Originally posted by @Mark Whittlesey: I would get a UPS Store (or similar) box instead of a PO Box.It costs more but is much more flexible (is an actual physical address, can receive UPS and FedEx etc.)I had a PO Box for a while and got rid of it for exactly those reasons. 

The storage closet is storing a shower head, a toilet, and whatever else you threw in there.

Again, the BiggerPockets store has some books on this topic, or you can learn about it by watching podcasts, reading blogs, and interacting on the forum.

I would venture to say very few landlords correctly hold their deposits based on local landlord/tenant law but as long as the money doesn't walk away and is not wrongly withheld from tenants its highly unlikely wrongfully storing the funds will become problematic.

The one cost will be getting the units furnished, but if you live in the area it isn't hard to source a bunch of decent 2nd hand furniture on Craigslist or FB market

You can find everything you need to know in a grocery store to make Pumpkin spice loaf with almond praline dessert, too.

Again, the BiggerPockets store has some books on this topic, or you can learn about it by watching podcasts, reading blogs, and interacting on the forum.

But it could also be a coffee shop or an etsy store and the cash flow goes into real estate.

I agree with Michael and JohnYou may get a small premium above appraised value for furniture and future bookings but that is about it unfortunately.