Köi-Lö wrote:

Yes, and they got along ok. A nip here and there but otherwise they lived
in relative peace.

You forgot the part about it depending on the individual personality of
each fish.
There are females from time to time that cannot be housed with certain
females, or some that can't be housed with any female.
This needs to be said *each* time.
It doesn't matter if you said it a month ago, or 20 minutes ago.
All Bettas are different and that needs to be said each time. You
should always have a back plan as well if it doesn't turn out the way
you want it to.
It's also so much easier when the females are spawn siblings.
Males things so much easier, as their hierarchy was figured out long
ago when they were babies.