Good theory, but the problem is: Soon would not have lied. So while I see no problem in Soon omitting certain truths (Jedi lies) he would not have lied. So whatever Shojo told the Order must be what Soon told Shojo. It must either be what Soon (who had seen his wife getting eaten by the Snarl) thought to be true or what the others told him (Giard and Serini might have deceived him).
Given Soon was "there from the start" I find it unlikely Scribblers started with a massive untruth.