It Didn't Happen the Way You Think (by Robert Lockwood Mills)

[Gene C]

I can see a plausible scenario for Stanton coercing Mathews to invent this story.

The connection you mention between Stanton and Mathews is implausible to me.
Not only that, you have not presented any facts to suggest your scenario is plausible, just a couple of "could haves".
The "invented story" is your scenario of Stanton coercing Mathews. It's fantasy. You are grasping at straws.

I see no purpose in answering your leading questions regarding a letter you fail to acknowledge whether you believe existed or not.