I have a Meraki MX that is my firewall connected to a pair of MS switches doing my layer 3 routing. I have to configure a VLAN with the following for AV equipment. This traffic does not leave the VLAN.
The QoS settings on MS switches don't need routing so the outbound queuing is respected for matching traffic.
However you cannot move your audio LAN up to the MX if you require multicast support since the MX itself does not have IGMP querier nor PIM support. That task can only be done on your MS switch L3 interface.
So it's best to just match the traffic types on your MS switches or just trust what's coming from that VLAN and make sure your needed DSCP values are present in the DSCP to CoS queue mapping section.