Like you thought, if you get the two Astro Pan&Tilt package, you can have them do pan & tilt. For syncing there will be a cable in that package. I’m not entirely sure if you can do the pan&tilt with just the Astro rings, but at least you can use the Astro App on your mobile phone to program them. It’s supposed to have much more features than just the physical rings. Check it out.

I’m not associated to the Astro team, just a kickstarter backer who went trough all the specs and comments that I could find. Check the facts yourself, I take no responsibility. :)