Before listing it, I had lots of expenses, including painting, floor refinishing, plumbing repairs, staging, cleaning, etc.In a 1031 exchange, I purchased two small multifamily homes which also have some roof work, painting, plumbing, etc. 

A good HI will go over your house with a fine-toothed comb.If you can find an Ex (or Retired) HI that is also Certified, that would be even better, since they will understand the structure/electrical/plumbing systems in more detail than a regular HI...

You think through the major systems in the house (roof, exterior or tuck pointing, hvac, plumbing, electrical, unit turns, common areas) and if they are all new you should be good for a few years (5-10). 

For example, focus on demo and structural work in month 1, plumbing and electrical in month 2, and finishing (flooring, paint, etc.) in month 3.

@Ori Skloot can you give more details on the electrical and plumbing work you did?

You would want to check local zoning to make sure you could build more than one as a lot goes into that beyond just being close to plumbing, electric, and gas.When you mention "a lot goes into that beyond just being close to plumbing, electric, and gas," what are the top things people tend to overlook when preparing to build ADUs?

If I have a specific area I'm looking in I would call multiple agents to ask about the area.I also reach out to communities like this and ask for others' input as well as recommendations for a good crew- handyman, plumbing, etc.Visiting in person sometime in the beginning would be ideal so the neighbors can know you and help give you info when you're gone.And it may just be me but I like to partner with locals

This doesn’t mean anything is “off”; it’s just how I prefer to approach this.To address your other questions, the property listing states that it has a new roof, plumbing, and electrical systems, which I see as a significant plus.

But larger repair items such as appliances and mechanical, plumbing, electrical, roof windows doors etc should still fall under the landlord's responsibility.

Take this opportunity to upgrade your plumbing and electrical if needed.