You can update Sengled bulbs on Hubitat...I and others have updated ours since Zigbee FW update was added.
You have to use the "legacy" version of the Sengled driver appropriate for your bulb, which has the FW update option.
The white bulbs do seem to respect the setting for power state after a power loss/recovery, but the color bulbs do not. My color bulbs were updated and don't handle returning from power loss properly. So for white bulbs it should work.
