The only concern is that, being a newly formed LLC, there is nothing to go after.

To give solid advice the community will likely need more information, (where you want the vacation rental, how much you think you want to pay, any questions/ concerns you have) It is difficult to give advice with no supporting information. 

What are major concerns for the decision; and how many started out flipping their primary residence and rehabbing while living there?

I know this topic is about DC, but I have heard similar arguments with concern to areas all over the US.I do not believe that investors are to blame for displacing working families.

There is no "best' method, you gotta do them all in today's world. 

You have to know the buildings which are friendly to STR as far building management is concern.

Read The Straight Path To Real Estate by Kris Krohn to better see the methods and strategies I use Personally.

@chrispurcell - I’m more concern about the well being of the home owner.

That is my major concern, my other is just the curb appeal.

Curb appeal lacks significantly in addition to landscaping concerns.