The tear-drop plumes are written in the left-upward, right-downward stroke,
and are physically related to the backward plume, not the standard plume.
IF I understand your own analysis correctly, I think we agree on the basic
structure.
You've probably also noticed that the "rainbow" plume (a loose
arc over the <ch>), is also drawn in both directions - in one direction it
is rather innocuous, but in the reversed direction rather careful. On that
theme you may also have noticed that the "caret" (^) plume also has a very
rare reverse, also done carefully in that event.