After a week, I've got the Mother 3 wiki page into… some kind of state? I've sorted through and uploaded only a small subset of all of the materials; the rest is safe in a folder when time allows.
https://morguefile.wiki/Mother_3
New plan: I realised that there's more to do on the wiki besides new pages: creating templates, writing docs, improving the front page.
So for now, I'm going to alternate weekly between 'new page' and ‘admin’ mini-sprints. This week: CSS issues. Oh bother.
Hrm, not a ton of progress this week.
Got it into my head to hack some local modifications to the MsUpload extension so the generated code for an uploaded file uses the wiki's custom gallery templates, but the code wasn't trivial and the changes were more than I could handle in the time available. Will return to it on the next admin sprint.
(I did finally fix the CSS on the drag-and-drop area on the editor, though.)