You want to look for a fee-only advisor, and in particular a fee-only advisor that works on an hourly, one-time, or retainer fee basis.

The garage already has electricity and is currently serving as a shop/office with at least one dividing wall between the two.

I feel like a JR ADU with shared walls would make the property feel more multi family-like and that may not be as appealing to future buyers. 

At that point it comes down to how much do you want to retain them.  20 nights is a long time and a significant expense for them.  

You never know what is behind the walls of any house until you either start a rehab or there is an issue. 

Walls Remove/treat mildew (per surface) $15.00 Repair hole in wall $55.00 Repaint (per wall/ceiling) $40.00 Doors Replace door (interior) $165.00 Replace door (exterior) $485.00 Replace weather stripping $25.00 Electrical Replace light bulb $3.00 Replace light fixture globe $20.00 Replace light fixture $65.00 Replace electrical outlet/switch $15.00 Replace electrical cover plate $2.00 Actual charges may vary based on condition, vendor and/or cost of materials.

If you're a corporation, or an LLC taxed as an S-corp, then your business can retain earnings for tax purposes and you would not be taxed until it is distributed.

@Jaron Walling thanks and yes under rented a bit now.

You have a future on Wall Street...Joking aside, many syndications investments return mid single digit cash on cash returns in the early years...and your cost of debt will be 3-4% minimum; so, you won't make much of a CoC return during the early years and most of your return would come at the sale of the property.The answer to your question lies somewhere in between keeping no leverage on your personal balance sheet and max leverage.

While we don't have a ton of moisture issues here with basements, we have expanding soil issues and have to build floating walls in basements.