Did Darth Gravid have access to all the powers that the Ancient Sith possessed during the Old Republic era?

In James Luceno's book, Darth Plagueis, it is stated that Darth Gravid was the last Sith to have access to the ancient Sith powers - among these abilities was essence transfer. Luceno created the character of Gravid to explain why Plagueis did not have access to this more magical part of the force including ancient Sith sorcery rituals.

I have two questions about this.

1. Did Gravid possess the ability of the Sith Emperor's ritual - the one that destroyed Nathema and then Ziost which gave him basically immortality?

2. Did Gravid possess most of the ancient Sith powers? I think he probably had the ability to call upon many abilities, but a lot of those ancient powers were lost forever before Darth Bane - for example, that Sith witch ritual that destroyed all of Ambria.