Last night, I unboxed my 2nd EdgeRouter Lite and immediate updated it to 1.9.0, then applied the WAN+2LAN2 configuration and tested basic SOHO functionality. All worked fine.
I then uploaded and applied the backup config file from my original "production" 1.9.0 ERL, and it seemed to work just fine, inheriting all functionality.
Even though I didn't do anything to try out the dnsmasq implementation of the DHCP service (I didn't issue an CLI commands), I somehow found that my cloned ERL has a blank leases tab. My production ERL has the Leases tab populated. DHCP services and reseverations and everything else is working just fine.
Just thought I'd add this data point to the discussion, in case it's helpful.