Well, no, it's not. I don't base my belief on multiple attackers on the footprints. There is much other evidence that multiple people were involved. The footprints appear to agree with this.
The contrary position, that there was a single attacker, requires us to ignore pieces of evidence - including footprints. In fact, you yourself have claimed that the footprints must have come from only Rudy because you don't believe there was more than one attacker - that is a conclusion based on a false premise.
I know, I know...you don't believe the lone attacker is a false premise. However, to reach that premise, one must ignore other pieces of evidence. This is the problem with the FoA approach to the case - simply ignore or sling generalized mud at the evidence we don't like, and then posit our conclusion based on those false premises.
Sure, if one ignores all evidence involving multiple attackers, it's easy to make everything else match - but then we're ignoring evidence.