Well, it's kinda working now. After changing the interface name in the config from optX to carpX, the interface was set to LAN (should be pubWlan) by pfSense, and that was the reason it was not working initially in addition to a required reboot.
But, the CARP on both fw's are now master, and i cannot see any multicasted VRRP packages on those interfaces anymore. A solution/workaround is highly welcome.
Thanks.