Addressing some things mentioned above:
The “minimum uniform” … [is the neckerchief]
I believe the part of the Insignia Guide referenced near this quote was not meant to convey that the minimum uniform is the neckerchief, so I think that meaning was read into it that wasn’t intended. I think the quoted material was to clarify that the neckerchief may be worn with non-uniform clothing. More info.
the Scout Shop photo has a Den Leader with green not red pack numerals
This rule creates confusion. I wish the numerals simply corresponded to the uniform shirt type. E.g., red numerals go with blue Cub Scout, yellow female Cub Scout leader, or green Venturing. All tan uniforms should have the tan numerals regardless of program.
Shoulder loops, ribbon, on shoulder epaulets; the color identifies the wearer’s primary registered position in Scouting
That doesn’t make sense. The epaulets are an ensemble with the position patch. If your position patch is of a Cub Scout Den Leader, then you wear the blue epaulets. The primary registration is rather arbitrary and may reflect concerns totally unrelated to your current position, such as which unit or level is easiest to register as primary with, which unit or level you registered with first, etc.
Also, I am a Venturing Adviser, but my primary is as a Cubmaster. I would not think of wearing the blue epaulets on the green Venturing uniform shirt.