A LOT of cool stuff in there! I´ll try to simulate a few things on Dynamips tomorrow, if possible, to demonstrate it better!
Couple things I know for sure after watching those videos: Frame-Relay Multilink and PPP over Frame-Relay are in fact very easy to configure. You just have to do it with attention and nothing will go wrong.
Another interesting one:
Frame-Relay Multilink: Used to bundle interfaces together.
PPP over Frame-Relay: Used to bundle PVCs together.
One more thing that I didn´t knew (at least, I´ve never saw it that way) about Frame-Relay: We can have Frame-Relay configurations in the Physical Interface, Point-to-Point, Multipoint and PPP over Frame-Relay all in only one interface, no problems at all! You just have to configure the other side of the PVC accordingly and that´s it! We may have this type of scenario in the real lab!
Talking about the Lab, there are many good tips and advices about the exam itself, find here just a few:
If the lab is asking to configure several different PVCs, each with it´s own subnet, but it has a restriction to not use any kind of subinterface, that´s a good place to use PPP over Frame-Relay (virtual-templates).
Another one is if they´re asking for authentication in the PVCs, we´re supposed to use PPPoFR, it´s the only way to perform authentication in Frame-Relay PVCs.
And a LOT more! It´s definitely a MUST HAVE material for any serious CCIE Candidate!
I´m in a little rush right now, but I´ll try to simulate some scenarios tomorrow!