OK, it looks like impedance probe is very similar to HP 41941A/B but in essence - just a Pi-network.
I have used HP 41900A Pi-network fixture for LCR mode and it seems to work OK. There is configuration setting for using this fixture in LCR mode so it works "right out of the box."
E4916A lowest test frequency is 1MHz so it might not be the best for large caps or inductors.
Leo