The Solo 401k is a separate entity from you and there should not be an intermingling of funds.

Has separate power meters, separate water meters, and separate gas meters.

The question becomes if the deeds were never recorded then how is there a separate parcel number for the taxes?

Once you get the concrete and posts separated, you could probably get someone to take both items off your hands by posting it in marketplace or Craigslist.

I also am in the preliminary phases of building 11 units in Concord, NC.  3 Br/ 3Ba units which will be comprised of 3 separate buildings on lot

Making sure you are aware JADU cannot be rented as separate unit except owner occupied.  

Buy in an LLC to completely separate yourself from the property.

Also, do you have separate accounts to track the income/expenses for each property?

It made me a little sick to know that the seller picked this thing up for 100K less only about 6 months before i bought it but I purchased anyway because if Ive learned anything as an investor it is to run by numbers and not emotions.

The ADU (with a separate address) adds about 700sqft (2BR/2BA) to the existing 1100sqft (3BR/2BA) main home, with the additional sqft and bed/bath count showing up on the property's title report.