Overall design looks solid. I would also look to utilise some sort of captive portal for the BnB - and think of using tokens as well that you create and setup out of the Unifi gateway.
My HA is running on the main trusted network while all my IoT devices are on untrusted VLAN then i have a firewall rule granting the HA device to the IoT network.
I am not sure how Reyee handles the VLANs and tags but it SHOULD be standard - so setting them up on Unifi should propagate them through with little issues. I run a full Unifi stack so mine is seamless from that perspective. i HAVE tagged certain ports (CCTV) where necessary
The Zone based firewall makes doing rules much easier than what it used to be - check this out