Been a busy few days working on other things but finally wanted to close the loop here for anyone that encountered the same issue as me. Long story short upgrading the firmware and then reincluding the switch at S0 (instead of S2, as suggested by @PJones) let me successfully setup the z-wave associations. It looks like there is an issue with the Ilumin bulbs and S2 based on the support teams comments in my ticket, so will be satisfied with S0 for now.
Finally, the instructions provided in the post [HOW-TO] Hubitat: Setting Up "Scenes" in Rule Machine helped me get all the scene control items setup as well. All-in all happy with the setup now.
Thanks again for all the assistance on my questions.