Both Marc Brooker (lead developer on the AWS Lambda team) giving the talks at Re:Invent as I mentioned in the footnotes, and the official documentation that's out there will provide you with a lot of information.
There's a decent references section at the bottom, and having watched the talks and briefly scanning the Firecracker paper referenced, they do back up the writer.
That's a footnote section and to me the listing is only partially related to the text, i.e. the write up contains a lots more details on multiple components.
Thanks though for backing up this write up. That's +1 for confidence.
When I was at re:invent 2019 I joined some chalk talks which weren't recorded (or not published). Some of the hosts told lot of details of their internal infrastructure.