Ah - that’s clean, I like that. The 3-hex shape is the smallest approximation to a circle that’s not a single hex, and it’s easy to envision the creature being centered at the vertices of the three hexes.
Following from that, the unit can change facing within those same three hexes (from your diagram, from the Northward position to either the Southwest or Southeast positioning) for no cost during a march, and once before a hustle without a cost.
Any other repositioning, say to face the Northeast, would require a movement point (to shift the center vertex to occupy the vertex of the right and rear hexes). Would that sort of face change still be allowable under a hustle either before or during at some given cost in movement?
Also, the bit about movement passing through occupied hexes - let’s take the example of a ground unit in the presented position, marching one hex to the northeast, and at the same time changing it’s facing to the northeast (it’s front two hexes now occupy it’s previous left-most front hex and north-most right flank hex). Would that have been a legal move if another unit occupied it’s previous center front hex, and hence at some point during that movement it’s leftmost front hex would have “passed over” that hex? (the same would hold for a unit in either southern flank hex)
Or does it instead virtually squeeze itself through that left-most front hex and spread out into the new facing?
Does it move + change face like a solid piece, I guess, is what I’m asking. I’m guessing yes, but figured I’d throw it out here.
And since at least one of those paragraphs is crazy, here’s a picture. The cyan hexes are the unit, previously facing north. If it marches/changes face in the given direction, the overlap is the hexes that units could occupy to block that movement (or any movement, actually, for a non-flier).