Hope this gives you another way of approaching multifamily. 

There is an abandoned property in our neighborhood. It is a distressed property. Drug activity, a real mess. But it is the probably the largest house in the area, around 5500 square feet. Would be worth a lot of money...

How would you approach a seller with this sort of proposition?

It's easy to be a one-man band and offer great service - you just have to work yourself to death:(A percentage of your clients will appreciate this approach and be lifelong clients. 

My dad told me about Avery Carl and since listing to all her podcast and interviews I would like to take a similar approach to short term rentals, to lead me eventually into multi-family.

My tenant complain about every little things from noise I have given notice in advance 1, How do I approach to their complains 2, What is the appropriate time to start the builder to start working in morning 3, I put HVAC on garden unit and 1st unit so radiators were removed. 1st unit tenant wants their floor fix on radiator site ASAP.

He is approached regularly with strong opportunities around the country.

Add in GC overhead profit, soft costs and you could be approaching $250-280/sf.

I was approach by her from an acquaintance and thought to give her a chance to sell one of my residential home.

You may also want to research what each area has to offer when it comes to economic growth, sports, entertainment, and education.