It's finally done!
We had some issues with the custom them not being recognised anymore and the poor Mastodon documentation where some precious infos disappeared (we had to search web.archive.org to find something useful: https://web.archive.org/web/20190513231813/https://github.com/tootsuite/documentation/blob/master/Running-Mastodon/Customizing.md).
Anyway, we are now running Hometown v1.0.4+3.1.5, enjoy!
Generalist Hometown instance with a strong focus on community standards. No TERF, no SWERF, no Nazi, no Centrist.