I'm not a contractor and don't do anything structural, but I would consider my brother in law and myself - experts at tile, kitchen, flooring renovations. 

Hi, For a rental,  I have kitchen counter tops which are laminate and bathsinks/counters and bathtubs etc are standard builder grade.

I've included a preliminary floorplan below.My goal with this ADU is flexibility in terms of renting it out either short-, medium- or long-term rental in the future for income, as well as maximizing resale value (main property is 1300 sq ft 3/2) to someone probably with an investor mindset who would want to house hack.My main concern is whether it's a good idea to have 3 en-suites at the expense of having a small living room/kitchen area.

I am looking in Smyrna, GA area and I am more inclined to upgrade them as I will remodeling entire kitchen and hence do not want any trouble with load on the circuits.

Saw a house with a For Sale by Owner sign in a yard with tall grass and after some drama, we have a house.We have dealt with long term rentals for over 15 years, but not aggressively ( keep them rented and do some improvements ).This "old house" needs, updated HVAC, new roof, new kitchen, some broken windows, upgraded electrical, water run off issues...I'm just starting to clear the house out with multiple dumpsters and starting to get quotes.  

All the improvements I am doing is going under this category (new bathroom, new plumbling, new kitchen cabinets, new tile, new flooring, appliances, etc...)I dont know how classify my labor expense.

But Generally speaking the parts of the rehab process are:Demo/Clean out/exterior workMechanical/RoofSheetrock/Kitchen?

It could be ideal for a house hack as there are two separate entrances, each with its own kitchen and bathroom.

The apartment definitely needs work - mold/mildew smell in bathroom, old kitchen appliances, old water heater, zero closet space, minor flooding in the basement, etc.

Najeh,You will want to focus on investing in areas where basic improvements such as curb appeal and internal updates (ie kitchen/bathrooms) would support higher property values that you could refinance or sell to make your money back.