Can I use a Nighthawk EAX80 as part of MR60 (mk63s) mesh network

Will it integrate with the system like another satellite? No.

Could you potentially connect it to the system and have it work? Maybe?

I say maybe because I've connected extenders to my orbi network before and they worked. they didn't use the backhaul or integrate but they did work. 

But I don't have a MK system (or EAX80) to test it with to confirm 100% if it'll connect and work

maybe Christian_R knows if it'll function. 

Is there a reason you're wanting to do this instead of just using another satellite?