It's worth noting that the link on the page to the list of pictures contains a mis-transliteration in search of "banbutsu" for "banmotsu" leading to a blank result. Both are possible for 万物, but the prior is more common.
I believe this is the correct link to a full list of the Lost Sketches: https://www.britishmuseum.org/collection/search?keyword=ehon...
Wood block print maker David Bull produced NEW wood block prints based on these sketches: https://mokuhankan.com/subscriptions/reborn.html
He streams regularly on twitch: https://www.twitch.tv/japaneseprintmaking
Every few months I post this link again about how ALL comics (well, at least Japanese ones...) start from Hokusai Manga and this exhibit tells that story beautifully.
https://hokusai.anotherstory.world/en/
It's terrific, and touring for several years all over the world.
I got to visit the exhibit when it was in Boston's MFA in 2014 or so, and it was really awe-inspiring. They had wood blocks from period prints and it's just amazing what artistry was able to come from that. I got a print of Red Fuji while I was there, and it still hangs on my wall.