When I ran hackage2nix locally, it fixed the majority of issues. Paging through diff, some new appeared:

• gnome-keyring had libgnome_keyring changed to null
• webkit2gtk3-javascriptcore had webkitgtk changed to null (though some other packages like webkit-javascriptcore did not)
• qr-imager had libqrencode changed to null

Nah, it looks like pkgs.gnome2.gtk is still used.

When I ran hackage2nix locally, it fixed the majority of issues. Paging through diff, some new appeared: [...]

These name lookups are fixed by 5012521.

Thank you very much for your help!