Pretty sure I'm going with the Commuter(*sigh*), because it has a rear rack, and fat tires.
Everything is stock on these bikes. Any slight modifications anyone can see that make one of the bikes a good choice.
Specific questions that I have are...
1) would the carbon chainstays on the hybrid be a bad idea with the B.O.B. trailer?
2) The road bike will only take 25cm tires. Is that to skinny for a short tour on country roads?
3) Hybrid has a low spoke count. Should that matter if most of my weight is on the trailer?
If I love touring then I'll break down and buy a real touring bike and do a couple more tours this year, but for now I'll use what I have. I'm already $600 into my budget without buying a bike.
I'd go with the hybrid for the simple reason that it has lower gearing. After a few days or weeks pulling a heavy load up hills you may be looking for relief. I've been in that boat. One answer is lower gearing. The other is to lighten your load. Doing both is recommended. When I was young I toured on a 10-speed. I don't know how many teeth the small chainring had, but it certainly wasn't a granny. I wasn't carrying much, and I was young, and I made it.
Now I have a 27-speed touring bike with a 24-tooth granny gear. I'm happy with it. I wouldn't want to tour with that first bike.
If you really get into touring then you'll probably want a "real" touring bike. But I approve of your plan of using what you have and giving touring a try before you invest too much money.