After a year of fighting my family friend gave up.

I have had experience getting them to take them over, but they really put up a fight.

The important point being that "S" people are smart and self-reliant but have a very hard time delegating - they're using to being the "star" - and it ends up hurting them because you just can't do everything and you do actually need a team to have anything other than meager success (in my experience).I only mention it because 1) several of your comments (Angel) sound like they relate to those themes, and 2) I suffer from the same problem and constantly fight against it in my own head.Finally, unless you have gotten a lot of experience with real estate in your own area / back yard first, I would be cautious about spending a lot of money in an out of state investment.

We decided it was not worth putting up a fight over it.Are the numbers so good that you could spend quite a bit in legal fees and it still make sense?

You could do this, but then if they don't, you'll probably spend thousands in legal fees fighting to prove that since they accepted it, they have to remove it.    

We also charge pet rent per dog and limit to two dogs.I think it is worth fighting this one.

I challenged this because #1, the engineer himself says the chimney does not need any adjustment, he just wants there to be a warranty on it and #2 because I don't think a structural engineer has any right to say that a seller can only use Brand X piers...especially when there is not adjustment needed.After many rounds of my refusing to pay for new piers that were not needed the finance company agreed to not require the structural engineers signoff if I could get them the Olshan paperwork explicitly stating that the piers were warrantied...I got that for them and then they decided that the house needed to be physically inspected by Olshan, so we did that...then they required more paperwork from Olshan but that after I got that for them we would be clear to close but the original closing date had passed so I had to extend the contract, which I did...and then after all this was completed now they tell me that the finance company still requires the structural engineer's signoff, and now the engineer is saying that he will not do it because I have two different brands of piers and that is not acceptable.The buyer's realtor has told my realtor that they have pleaded with the engineer to signoff but he will not do it.I do not see any justification for the engineer to say that it is unacceptable to have two different brands of piers...especially since no work is needed and this is apparently just a fight for a warranty.  

If they fight me on it the lease is up in 3-4 months and I will simply not renew it.

Most RE Agents want the deal to Close so they can get paid, not have a conversation that turns into a Thanksgiving Dinner fight over whether Ohio should beat Michigan or that Hillary really DID launder money through the Clinton Foundation.

It's unfortunate that your agent didn't want to stand up for you and at least fight for you to try to get it back.