His act of peeing in my yard is symbolic of how he thinks he can treat me. I feel if I don't push back and address some of these issues there will be more serious issues to deal with.
First: I don't think peeing in your yard is cool, but I do agree with others that if he doesn't have a convenient bathroom (i.e., yours) then I'm not sure where he's supposed to go.
Second: this is a needlessly complicated way of looking at this issue--for you. Why make it harder on yourself or more serious than it (necessarily) is? It's symbolic to you; he may or may not have thought it through at all. In fact, I highly doubt he knows you were watching him urinate.
What kind of "serious issues" do you anticipate? For the life of me, I can't think of the kind of escalation you seem to have in mind as a logical consequence of such an (admittedly, careless) act. He still wants to get paid, and has some stake in quality workmanship and future business, does he not?
If you are fearful of serious property damage, or theft, or defecation, or ... whatever it is that you feel a need to take a stand against, why not fire him right now?
Well, she's already had property damage. He broke the corner of her patio by being careless of her stuff. He disregards her schedule and pushes her around, verbally.
So I totally get why this seems like the core of the issue for the OP.
However, I think that addressing the other issues is a stronger leg to stand on.
If he has any sort of boss, go straight to that person. If he *is* the boss, tell him, "any recommendation I ever give you is going to be contingent on your working with me instead of pushing me around. And I'm not happy that you broke my patio, because there was CERTAINLY room for you to drive around it instead of over it. I'm getting a bid for a repair, and I expect you to pay it."
Though--honestly?
Do this:
...he made such a huge mess in the backyard and refuses to clean it up, I have to have someone come in and fix things before the pool is erected.
...He kept telling me that he would grade the piles of dirt that he was piling up all over the yard but then he just left it there.
...He also drove the machine over my concrete patio and cracked the corner right off!
Wait, what? Here's what I'd do - call him and tell him something came up and you have to postpone finishing the install for a week. Then call someone else and have them come out and give you a quote to do it right, including correcting the damage he's done. Finally, call him back and tell him you've decided not to have him complete the job and you'll send him a check for the work he did MINUS the cost of repairing and cleaning up what he ruined. This guy is a jerk. You hired him, not the other way around. He's not doing the job you hired him for, in fact he's breaking things and making a mess in addition to not even doing the work correctly. Get rid of him. 
I agree with this completely. Postpone the job. Get somebody else out to finish the job so that you don't have to re-do it later at greater expense.