I sampled a little of Osby's
Channel Three & Branford's
Bloomington...very similar.
What I hear are piano-less Trios(which I love; nobody playing "chords").
No "chording instrument" being present may be the reason you're having trouble hearing a "chord progession"...as for "no regular beat"-
Time can be bent, displaced, or played "Free"...this stuff ain't about backbeat!
Also, what I heard seems to have a grounding in Post-Bop.
One aspect of the Harmoldic component is the sensation that everyone is 'soloing', even in an 'accompanying' role(like bass & drums).
Is that vague enuff for you?