I try to read what is written, without skipping some words, without adding some words. I expect you to do the same, please.
The rule nowhere requires the character to have an exact multiple of the other model's footprints.
To fit neatly inside the unit is enough.
Sure, exact multiple footprints do fit neatly. All the examples you provide are perfect examples of multiple footprints.
But if multiple footprints are a solution, it is nowhere written that it is the only, mandatory solution.
Here, I try to investigate an alternative.
I fully understand that if the WP wanted to join a unit of 9 DG, placing him anywhere inside the first or second row would disturb the ranks behind him. With no solution to place him inside without disturbing the unit, he would have to go on the side.
But here, I am talking specifically about a very small unit of 3 DG.
In the case I examine, the 3 DG together make a rectangle 150x75.
Suppose I had a 4th DG, that would make a "L-shape" unit, made of the same 150x75 rectangle with a 50x75 extension behind.
Adding a WP instead of a 4th DG makes a "L-shape" unit as well, it's just that the extension is smaller, only 25x50.
How can anyone argue that one L-shape is less neat than another L-shape?
They are both legal, even if they don't please some of you.