Wonderful, thank you! I was hoping it would work that way, but figured I'd ask here first to make sure there was no "gotchas" in regards to using zones that aren't actually wired up. With that confidence now, I'll give it a whirl this weekend.
I use IFTTT for various things, but didn't consider using it for this issue. Good idea. Right now just using the the common orbit timer that's the number one on amazon (not wifi or anything). I just did a search and see a few connected spigot timers such as Melnor RainCloud, RainRobot, and Gnome. While not an extensive search, none seem to support IFTTT, unless you know that one does?
Otherwise will stick with the Orbit, and eventually will go through the work of possibily hooking up the soakers to the Rachio. Thank you!