I have a Tax Professional that is including home sale under Capital Gains Schedule D *and* depreciation recapture under Form 4797, which is why I am here trying to understand what is actually correct.

Are there vibrant businesses and jobs that the newspapers are not reporting on correctly?

We ask the person who the real owner is and if they are not correct, ask them who they are in relation to the applicant.Good luck!

It took them 2.5 hours to figure out the correct lockbox code so they wasted 3 hours of my time and my brother’s time as he had to drive to the unit twice to gain access to the property. 

Good luck  You are correct that I do not yet have a ton of investing experience. 

Here's my take on your list:5 - 100% correct. 

Ditto to everything above haha that is standard but unfortunate it wasn't set up correctly for you in the first place.

What @Alyssa Wright stated is correct.

Assuming i am correct, it does not apply to a garage being converted to an ADU.  

If I was doing this first thing i would do is talk to the county office that control sanitary and see what they will allow. this of course assumes your zoned correctly etc..