The basics is just that VPC, VKB and Thrustmaster are compatible with their own equipment.
Thrustmaster grips can be used on VPC bases and on VKB bases with an adapter.
VPC and VKB grips are incompatible with eachother.
VPC grips are a mixed bunch. Some are compatible with Thrustmaster bases, with limited functionality as TM don’t support axes in the grip.
Yeah, you’re right. It IS confusing 