Oh my gosh what a nightmare for you. Sounds like these are some of the most miserable people on the planet... nothing to do but complain about everything.
It sounds to me like you have gone WAY out of your way to be cooperative during this process. I mean, what did they expect??
And re: the grass dying, HELLO, they could use a hose and sprinkler like those of us who don't have the LUXURY of a sprinkler system!
They will probably rip out the new sprinkler head just for spite.

Ok, done helping you in your rant!!