I feel your pain, the same thing happened me a few months back. Sorry for your loss.
I don't think you should try again, not for now. When my sorority died off, a female survived. Then she died, and after 2 months or so I got a new male betta. The new sorority would remind you too much for a few weeks.
You can get a male, that way you don't have to lose that
EDIT: What were their symptoms? I don't recommend both, guppies introduce disease quickly if not quarantined. That's what happened with mine. Mollies prefer brackish waters, your plants wouldn't like that.