I ran into the same problem before. You need to enable DHCP for the host connection in network manager (doesn’t matter if WiFi or Ethernet) for the VMs to connect. Libvirt networking seems to need it.
As for why Whonix doesn’t connect while others do, could be an overlap of static addresses or maybe by having dhcp clients, the other VMs resolve their connection problems somehow. This didn’t seem to matter in my case.
Re-enable DHCP on the host.