Hi Ilya,
Virtual EXOS doesn’t support anything that requires a hardware packet processor. This means that IPFIX, VxLAN, MPLS, VPLS, Policy, etc. won’t work. You can configure them, but the data plane won’t work. MLAG, EAPS, and VRRP, however, I believe will work fine.
As Patrick mentioned, the Virtual EXOS platform is not able to be "stacked."