Officially benefits are personal, also bear in mind that the KLM flight leaves during "rush hour" and therefore you won't be allowed any guests, even for a payment due to the lounge renovation.
As for SP, in AMS I never had issues bringing a guest through SP security & boarding, no experience with CDG and I suppose it's always the case of YMMV based on the dragon at the entrance to the SP queues.

I would advise to avoid JNB if possible.