Virtualbox networking help

[PopeyesPappy]

So I’m a complete newb with virtual machines and have some networking questions. I know what I want to do. I’m just sketchy on the implementation. Here is what I have: Dell R710, 2 hex core processors (12 cores/24 threads), 192 GB of RAM, 4 x 300 GB SAS drives in a RAID 5 array. I have an Ubuntu 20.04 host running Virtual Box and three virtual machines each running Ubuntu 18.4.

I want to setup the networking like this:
en1 - host: 192.168.6.56, vm1: 192.168.6.57, vm2: 192.168.6.58, vm3: 192.168.6.59
en2 - vm1: 192.168.9.57
en3 - vm2: 192.168.9.58
en4 - vm3: 192.168.9.59
All 4 machines will share a nic on the 6 VLAN. Each of the three VM’s will have a dedicated nic on the 9 VLAN.
 
Question 1 is will this work?
Question 2 is do I manage all 4 NICs and the addresses at the host level?
Question 3 how do I setup the VM’s in virtual box to use the 2 different physical NIC interfaces? I think NAT for en1, but I’m not sure about en2-4. Bridged maybe?
 
This isn’t an issue in the production network because each of the machines runs on dedicated hardware.