@audphile1 I'll mention this for umpteenth time, when using usb dac,optimization is absolute key!. Vast majority of servers have rather poor usb rendering, reason for all these usb filters, renderers, other thingies. Right off, I'd say this is your weakest link, even beyond needing lps for the FMC's.
Very difficult to get beyond clutter when optimizing streaming networks. The only means to get beyond this is with the very top tier servers with optimized INTERNAL usb, network ports, or whatever output port one prefers, these also have built in top tier lps so no need for external lps. Another means to simplified system is slightly lesser server with top tier streamer/dac, server still must provide top tier network out port to retain simplicity. With all the streamer functions built into dac, one can bypass all the usb or any other preferred port issues. Get rid of all port issues, half the battle of clutter has been taken care of, only ethernet optimization remains.