The features of hakaturou glyphs are not so many - no arms and no real legs, only a head of sorts and a body which can be straight or curved (with or without a 'knee'). How the head and its jaw is designed carries meaning, though:

In Ca8-28 the jaw is defined by two straight lines (like a wedge) and the head is looking backwards, not up as in Bb6-17 and in 'Sunday'. Presumably this is a sign referring to the back side of the month (descending moon). Ca8-29 has a jaw formed not so different from that in 'Monday-Wednesday'. Possibly this type of jaw means 'waxing'.

But then, in Bb6-17 the middle 'person' will be the waxing new year and the one at right (with flames at the back of his head) will be the old year. The old 'person' should be looking backwards. And the 2nd half of the 'week' is the old part. Both examples having non-waxing jaws.

In Eb8-25 the old one is at left (as in Ca8-28) and the new one at right (as in Ca8-29), the more natural order. In Bb6-17 this natural order is disturbed by having a triplet instead of a duo. The triplet forces the central figure (waxing) to the center.

The growing jaw is at right (as it should) in Ab8-84. Also the two 'legs' at right exhibit the same growing shape, especially the top one.