HI Gianpiero
1) 5.0 is a combined engine and any firewall rules/network configuration is commonly available to both masking and virtualization engines.
Adding a NIC to a Delphix Engine and configuring additional IP addresses is supported and is simple to configure. Regarding adding a new NIC specific to a application; I will defer to network teams.
2) Sizing depends on the throughput requirements, 128 GB is enough for a combined OVA; for specific needs please contact support.
Thanks
--Hims