I assume there is zero or almost zero appreciation and that’s the reason you aren’t selling tax free?

Your main issues will be eggress, as usual in a basement.

My company for my personal house covers my STR very reasonably.

@Jason Wray, The reason that our shop is pretty hot about your post is two-fold, we do all of the things that you are implying that we don't (other than government loans, we don't work in that space). 

Our main issue is these properties are owned in an LLC.

Having a high W2 income I want to protect income/personal assets which is the reason for LLC. 

So if, for whatever reason, laws change and you can't rent it out on Airbnb, etc, it still cash flows if you need to rent it out to a traditional long-term tenant. 

He is correct that a single ADU in a single family zoned area is unlikely to return as much as the hands off cost and is one of many reasons that adding a single ADU in most single family areas is not a good re investment.  

Reason that is bad is 2-4 units were the first to go sky high in 2020 to 2022 and now rents do not match the market if your getting financing.No point having a mortgage of over $2850.00 on a $420K home if the rents on a Duplex are only $1250 to $1350 a door. 

Flipping houses is a great way to create huge profits, raise private money and create marketing content around your remodels (the reason HGTV is HGTV).