Would I just replace the parent name in the network devices to be lxdbr0? - yes you can do that.
Does nictype bridged stay the same? - yes
Would DHCP be disabled or do I need to explicitly state that somewhere? - it would be enabled on the lxdbr0 network by default, use lxc network set lxdbr0 ipv4.dhcp=false ipv6.dhcp=false to disable.
I use host_name to specific the port name in OVS, this should still work since it’s still an OVS bridge, but now managed by LXD? - you can still use that.