I’ve used Fastmail with a custom domain for a few years now… (5+?) and have been really happy with it. I wish it was a bit cheaper (or had a better family plan), but it works well with my terminal email client (mutt).
The web client is pretty quick and I use the calendar there all the time. Fastmail supports all the normal standards such as CalDAV, so you can use it with third party applications.
I used to use VLC for music, but these days I use Symphony to play local files on my phone. VLC tended to struggle when scanning or indexing large folders (which it did all the time…), while Symphony is a bit better at that. That said, I still use VLC for video and for casting things from my DLNA server (VLC supports Chromecast).
For ebooks, I’ve used Librera FD and that has been mostly OK. I’ll checkout the two you mentioned though. Thanks!