However, since I was the Project Lead for the Spyglass browser team, there is one correction I can offer: We licensed the Mosaic code, but we never used any of it. Spyglass Mosaic was written from scratch.
In big picture terms, Marc's recollections look essentially correct, and he even shared a couple of credible-looking tidbits that I didn't know.
It was a crazy time. Netscape beat us, but I remember my boss observing that we beat everyone who didn't outspend us by a favor of five. I didn't get mega-rich or mega-famous like Marc (deservedly) did, but I learned a lot, and I remain thankful to have been involved in the story.