Dimmer switch and zigbee connected bulbs?

Your Cree bulbs are zigbee, right? Not Wi-Fi.

In any case, one of the advantages of smartthings as a multiprotocol platform is that you can use any switch that works with smartthings and have it control those lights. That’s pretty common. The switch will talk to the hub and the Hub will talk to the lights. (As @anon36505037 mentioned, just don’t have the switch control the current flow to the bulbs. Do the communication wirelessly.)

See the following thread:

Also, this: