Hi,
Ok, I would configure a new vSwitch and port-group to place the Mikrotik and Wanos wan0 in. Leave the other virtual machines as is and place the Wanos lan0 in this vSwitch and port group where the servers are. Enable promiscuous only on the port-group level. In this scenario no VLAN's are required since two different vSwitches are used. The one physical NIC is attached to the Mikrotik and Wanos vSwitch.
The same IP address space should not be a problem. Configure a default bypass rule as #99 to pass-through all traffic. Then configure specific rules for the servers e.g. src 172.16.50.128/29 dst 172.16.50.192/29.
Recommended steps:
Update to v.3.0.2
Click on the get trial button to send through the registration token, in order to generate matching keys for the speed you require? What is the speed of the WAN link?
Play with deduplication / byte-cache level 0 to see if it makes a difference. Sometimes the VM's are already deduplicated to an extent and in this case the feature can be disabled to reduce hardware resource dependencies.
Add the remote side Wanos address into the MultiSite table to enable stream compression and packet loss recovery.