You want to inflict a level of pain for them to continue to occupy *your* house once you've sold it that will encourage them to go - unless, of course, the objective is to maintain them as a long-term tenant.

If you add a 2nd story,  you will basically be building a new house which is a pain. 

You don't mention any pain that they seller has.

I have mixed emotions on this one of the pain points is the pool addendum has been complained upon several times which is annoying. 

This ended up costing around $25,000 (not including loss of rent during this time).The painful part of this is that at least as of right now, his insurance is saying this is not covered as part of his policy.

I appreciate any insight or advice you might have.p.s. my first home was a short sale so I know they can be a pain, but worth it with patience! 

Generally, that's why I wait until about 60 days to limit my pain and try to play the "I am being more generous then the law requires" which helps to buy a few sympathy points.

Newbie to investing and real estate  here, so sorry in advance if the answer to this is painfully obvious to experienced investors.I'm trying to educate myself on the possibility of flipping houses in the greater Boston area, an area from what I gather is generally very difficult and competitive to find a good deal in, and an area generally with very high acquisition costs (e.g., high risk, high reward). 

Painful considering it is saving you 5% when it could/should be earning it's keep at 10%+.

This way they know the pain of vacancies and other expenses.