[Calzifer]

> Or is there some particular criteria an init system needs to satisfy to be included, that systemd doesn't satisfy but the others do?

Reading the first sentence on that page was to much?

"Init Freedom is about restoring a sane approach to PID1 that respects portability, diversity and freedom of choice."

systemd fails on the portability criteria.

Apart from that, why should they invest there limited time to include systemd? Devuan is Debian without systemd. If you want systemd install Debian.