But how?
Ehh, edit the meta data or so?
Better ask F-Droid about how to do this.馃榾
Here there is the wiki article about it.
As with #2 the metadata directory is already there it may be the simpler thing to do, just add the screenshots to the fdroid repo and update them when something changes.
The new page is here and I think using the "app鈥檚 source repository" is a better and easier idea than using the fdroid repo again (and needing to update it).
OK, I added all the descriptions in all the languages. I hope it is the correct format, I did actually not use fastlane because it does not work on Windows.