.• I estimated that the repair costs would be close to $10k. • My final plan is to rent the units as long and medium term rentals after refinancing and buying out the seller.• I do not currently have enough liquid capital on hand to put down 20% for a DSCR type loan.

You didn't mention what your PITI is and what kind of income your ADU brings in but I'm guess you're close to living for free.

Obviously aware of the major costs to consider (down payment, insurance, closing costs, etc) but was looking for help on other costs to include during that evaluation.Rehab costs will be specific to each property but just wanted to make sure there wasn't anything major I was missing! 

The biggest draws for investors are not needing to provide income docs (no W2, tax return, paystubs etc needed), DTI doesn’t matter, you can close in an LLC, and not all lenders report the debt to your personal credit (so it doesn’t affect your credit score or DTI for future conventional financing).

I have one rental close by, rent amounts are crazy. 

The profit would only be calculated after all cost to include closing cost (realtor commissions included) were deducted.

Still I consider my health my absolute greatest asset, aside from perhaps my close relationships.

You want an aggressively negotiated purchase price, low closing costs, lower property taxes, affordable insurance, minimal HOA fees, and competitive property management fees.

I wanted to self manage, and hence was thinking of focusing on the areas close to where we live.

If so, you could plan to market about 60 days before lease end or even sooner if their house is ready earlier, so you can close as soon as they are out.