Dude you created a LOOP.. .that is going to cause all kinds of ODD Shit!!
You you can not run it this way be it home, or a lab or an enterprise. It will not work!!
I already suggest you could try using the igmp proxy.. But if all you need is mdns discovery, then yeah avahi might work.. Can tell you that getting chrome to work across different L2 is going to be a PITA..
Use something else would be my suggestion. Not sure exactly in what context your using it in..
If you want pfsense to filter between the bridge.. Then your going to need another physical interface on your vm host, so you physically separate the L2 you want to filter/bridge between 2 physical networks via different switches. Or a smart switch that you could isolate the L2 via different vlan tags.. You could then bridge across these 2 tags vlans and make them the same on pfsense doesn't have to know about the tags, etc.
So with a smart switch you could do something like this..
bridgewithsmart.png
You create 2 different vlans on your switch.. You then isolate these different vlans on your esxi into port group for each vlan.. Then you connect these port groups to 2 different vnics on pfsense that not using tags.. esxi will strip the tags let the port groups handle the tags..
You bridge these interfaces on pfsense.. So you have 2 isolated L2, that you have bridged into a single L2 via pfsense.. So computer on Y not talk to X unless it goes through the pfsense bridge.. Now you can filter and say no Y can not talk nas on vlan X via L3 filtering..
But if your switch is not smart and can not isolate the vlans.. Then this can not work!!!