We are looking to grow this into many buildings and units but are going to need joint venture partners in the future.

Ok so if your goal is 100k a year income you are going to need to invest around 1 million at 10% return over the next 15 years.  

Gas heat might need a 6A fan while electric wall heaters could use 30A a piece.So if you've got electric everything and plan to add the same to the ADU, you're probably going to need either independent service for the units or upgraded service to the main house (e.g. 320A service) with a sub-panel in the ADU.

Going to need more information on location, type of construction (block or metal frame), parking, zoning, etc.

Also STR are a hospitality business so you are going to need more availability then a LTR.

Since you're second-guessing the Title Attorney's advice here you're going to need to get a second opinion from someone with more experience with those specific issues.

Properties that take a long time to rent in the good times will be very hard to rent in the bad times, when you are most likely to need the income.

From the exterior it appeared to need a lot of work, but it was purchased for only $60,000, so depending on the condition of the interior, that could become a great deal.

I have a lender but you are going to need cash flow. 

I gathered it was a hot button issue from the tone of the supervisor who appeared from behind the planner at the desk I was speaking with.