I have two question , need peplink support help me confirm :
Q1.What is the maximum number of Virtual WANs that SDX Pro can support?
Q2.Referring to the diagram, can Virtual WAN and LACP be used simultaneously between the SDX Pro module (EXM-4F) and the switch?
Yes they can- Virtual WAN on VLAN just specifies a vlan tag to use as a wan, that vlan can exit just like any other vlan (via a port set to access mode for that vlan, a trunk that carries that vlan or an lacp that carries that vlan).