"This is planning. We assume for now, that you've read the documentation."
Sounds like you are giving the whole machine to the first VIO logical partition, so there is no hardware to install another... and you cannot run a "WPAR" on a VIO server...
Not being rude but it does sound like a basic understanding deficiency of how PowerVM works.
>>>>read the docs.....
Make a PowerVM/VIO LPAR with one ethernet adapter, one scsi adapter with a disk, maybe a fibre adapter. Install PowerVM/VIO on it.
Do it again.... so you have a redundant/dual VIO server layer.
Then on both of these VIO servers virtualise some form of storage, vscsi, npiv, lvm, for the client LPARS.
Set up SEA adapters on the dual VIO servers, so you have redundant networking for your client partitions.
Set up virtual ethernet, vlans, Etc. for the clients to use.
Then configure your client LPARs partition profiles for your AIX / IBM i / LINUX client LPARs.
Then boot and install them....
Any of this sound even remotely familiar...
If not then at least you have some terms to google for help.
It's not really like any other form of server virtualisation but it is by far the best.
Good place to start reading:
IBM PowerVM - Getting Started Guide
HTH