Won't know until launch date/s.
Wasting your time asking for info on unreleased product/s here.
I also want to know about Radeon VII crossfire.
I know that AMD cut off the R7 PCIe 4.0 and IF Bridge.
But I want to know if it supports the traditional AMD CROSSFIRE
ok...Radeon VII support AMD Crossfire
Now you can use mGPU in DX12.
About DX11, the driver already has the AMD Crossfire option, but the game is not yet supported.
I believe that the follow-up version will soon improve it.