Is this possible? I want to sync all my Hubitat connected devices to a Home Assistant instance so that I can then build nice UIs and sync device states between the two.
Will I need to have Zigbee/Zwave dongle on the HA instance even though it won't be used?
There is an unofficial Hubitat integration you can install manually or using HACS: GitHub - jason0x43/hacs-hubitat: A Hubitat integration for Home Assistant. This gets you Hubitat devices into Home Assistant via Maker API on Hubitat, and it should do what you want. No need for Z-Wave or Zigbee radios on Home Assistant then--the devices live on Hubitat, so it doesn't matter.
EDIT: This is the same integration as the above, just a different link.
EDIT 2: This is literally all I use Home Assistant for, and I've barely even customized the UI--just some history graphs (and current states for some devices) with a minimum amount of effort from me.
I'm up and running and loving how flexible Lovelace is. I played with Home Assistant 3-4 years ago before settling on Hubitat and its come a long way since then. I already have a dashboard up and it's looking great already.
Plenty more to do because I have hundreds of devices but it's going to be fun and flexible.
I'll stick with Hubitat for everything other than dashboards.