So, I’ve got the wireless keys programmed into the alarm. Everything seems to work. The only “wild card” here is the range of the things, because the receiver is mounted a little farther away from the garage than I’d like. If the range turns out to be a problem, I’d expect all of the buttons on the keys to work inconsistently. What I’m seeing in practice, is that the garage door button works consistently, but the disarm button is spotty. I get the same behavior with both keys.
I don’t really have an explanation for this, so the first thing I’m going to try is moving the receiver closer to the garage. I’ll mount it in the new spot temporarily, and see how it works (in particular, it needs to still work with my existing wireless zones). The other thing is, I still haven’t installed the status transmitter module. It doesn’t seem like that should have anything to do with it, but I’ll go ahead and install it at the same time, and see how things go.
Followup.. turns out the spotty behavior did affect the garage door button after all, so most likely, this was simply an issue of the signals not getting to the receiver. My hypothesis is that the house’s aluminium siding was interfering with signal propagation. The fobs seem much more reliable now that I’ve relocated the receiver.