It may be worth backing the closing date off some (appraiser taking like a month here anyhow I hear, so you may have time and her behavior probably backed off the date anyhow).

In that letter,  list the dates and times of problem behavior and in the letter state that these tenants are disturbing you and your wife's right to "quiet enjoyment" of your property.  

At any rate if you can recognize this behavior as the type you don't want then yeah give him the boot.

I feel offended by her behavior towards me. 

The moral of the story here is be careful about behavioral issues when screening.

Obviously I could have fixed that specific thing first (it's cheaper to re-route the downspout and cap the drain than it is to confirm that the underground pipe is actually broken, and based on the verbiage in his letter, he appears to feel the re-route is an acceptable resolution to his concerns).I met with an attorney friend, and he feels that the neighbor's behavior is harassment, and that now is the time to send a letter from an attorney telling him to knock it off.

As if that negates the other problems - that they post on BP wanting advice for, then for some reason justify the tenants behavior because they pay on time.Now here you are saying the lack of communication and their intent to get a stealth cat must not really be a problem because they mow the lawn.That's not logical.  

Even though many of these disordered people are not sympathetic (in fact they can be downright infuriating), I still think we, as a society, will be better off if we actually look at the root cause of their problems  (while still holding them accountable for behavior).

His wife is a nice gal who never bothers me and I don't think really cares about the issues that he brings up to me, if he was more like his wife, I would not be considering terminating his tenancy, and I have talked to him in the past about his behavior, told him I would not tolerate it and that if he didn't like the way I did things, he could move and it did get better... for awhile until it recently started again.

This kind of behavior can happen when a tenant is trying to get out of a lease.If you have a property manager, is it possible they're over-charging you for maintenance issues, to collect more fees than necessary?