With the Zooz, you've got two options. I believe their switches and dimmers in "smart bulb mode" still internally track on/off state and level, so one option is to use Hubitat's built-in Mirror app to push changes from the switch/dimmer to the bulbs.
The other option is to treat your Zooz as basically a button device. For example, besides (possibly) on/off events, pressing the top or bottom paddles should generate events on Hubitat like "button 1 pushed" and "button 2 pushed." What I'd recommend is setting up an app like Button Controller or Rule Machine with a button device trigger (or use a community app that, IMHO, makes configuring these with lights easier--but all the same idea in the end). Then create actions for the specific button events that manipulate your bulbs. For example, "button 1 pushed" should probably turn on both of your Sengleds, and "button 2 pushed" should turn them off. To get the full effect, you can add things like "button 1 held" doing a "Start raising dimmer level" and "button 1 released" a "Stop changing dimmer level" and similar in the opposite direction for button 2, which will give you smooth up/down dimming like it would if it were controlling "real" bulbs.
As an aside, you could create a group instead of controlling both bulbs directly. This may cut down on Zigbee traffic and improve reliability, especially for commands set in quick succession. However, groups don't support the "Start Level Change" and "Stop Level Change" commands like the individual Sengled (or even generic) bulb drivers do, and two bulbs isn't a ton, so you may just want to use them directly here. Up to you, however!
PS - I should also mention that I prefer the second option. The first is more intuitive for some people, but I think it can be problematic sometimes (e.g., if you manipulate the bulbs directly via other means) since it is one-way only. If you think of the switch/dimmer is now just a remote/button device, I think the second way makes sense.
