If I had to come up with a name it would be Fritz.
It's worth looking at Marvin Johnson who took Baker's affidavit. This is Johnson's undated report:
https://texashistory.unt.edu/ark:/67531/metapth337554/m1/1/?q=marvin%20johnson
It's basically Savage's story but the encounter is taken to the 4th floor; more like an early crude attempt to get Oswald closer to the 6th floor. Most interesting is the last paragraph which forces the question: why didn't Baker mention any of this in his affidavit?
On the day of the assassination Truly gives a statement to the FBI. In he he recounts, precisely, what is known as the Second Floor Lunchroom Encounter - second floor, Baker enters lunchroom gun drawn, Oswald is alone in there, Baker asks if he's an employee, Truly confirms he is, both men carry hit the stairs.
Who is providing Truly's narrative?
Why is it different from Baker's?
When did Fritz have time to give Baker his "tailored" account?
Why doesn't Baker include Oswald in his affidavit if he is sat right there at the time he is giving the affidavit?