This may not be pertinent to your problem(s), but, I was having great difficulty getting Multiplicity to control the remote machines. I could get the video OK, but no KB or mouse control. Sometimes it worked, but mostly not. On a whim, I brought up file explorer and clicked on network. The remote computers were not listed. I did a refresh of the network and one of them appeared. The other machine appeared on the network AFTER I shared a folder on the remote machine. After both machines showed up in the network area of file explorer, Multiplicity worked OK. I then had full KB and mouse control over the remotes. I think the control paths of Multiplicity may be linked to whether the Win OS can actually "see" the machines on the network. It appears that other remote control software uses UDP type protocols and not IP oriented protocols. Addressing the machines via MAC addresses rather than IP/netbios/.etc would be desirable.
Just an observation here. Also, Multiplicity seems to go to sleep after a while and won't work until you do a restart of it from the task bar icon on the right side of the task bar. Again, just observations from my machines.