Unusual setup question

I’ve been following The Gon for several years and have learned a lot and haven’t had much to contribute, so I sit back and learn.  Now, I have a legitimate question on a particular setup that I’m planning to see what you guys think.  
I have two systems in the same room, one is a two channel in the living room and the other is an in ceiling setup for whole house background listening.  In the two channel, I have a Node2i as streamer, Krell x64 DAC, Mark Levinson Pre and Essence Sapphire amp running to Canton Karat M80dc speaker.  The im ceiling system is NAD BluOS streamer to Rotel DAC, B&k Pre to a couple Carver M1.0t cube amps.  I have two M&K passive subs for the 2 channel system and two built in ceiling DIY subs for the whole house system.  Currently the M&K subs are powered with a Dayton Sa1000 sub amp and the DIY subs are powered with a pair of Adcom 565 mono’s and Dalton LF crossover.  I have two Crown XLi 3500 pro amps  that I intend to use for the sub amps and get the sa1000 and Adcoms out of sub duty.  Here are my questions

1. I intend to use a Minidsp for sub crossover duty, probably a 2x4 HD, but I intend to use input 1 from sub out on the Node2i and input 2 from the sub out on the B&k preamp.  Again, node2 is one system and B&k is a separate system.  Output 1&2 would be to system 1 subs and output 3&4 would be to system 2.  Would crosstalk be something I should be concerned about with this approach?  
2. My main concern with the above setup is ground loop hum induced by two separate systems running single ended from separate power supplies from the wall.  With this concern, should I move to a balanced Minidsp, Proamps have balanced connections but the sub out of both Node and B&k pre are single ended.  Would using two Minidsp 2x4hd help in any way with the likelihood of eliminating the potential for ground loop hum?

I have considered that I should just try it and see what happens, but I don’t want to get one or two 2x4hd’s in to it to find out that a balanced MiniDsp Flex would have solved it.  Obviously, the reverse is the case as well.  Meaning, no reason to go balanced if it’s not truly balanced from in to out.  Any advice would be appreciated. 
 

Speed