What I find interesting not only are they related somewhat they are similar appearance, same height etc but they are also both into selling real estate.
Lots of people may have appeared vaguely like Murat and I find it possible that his face splashed all over TV as a "prime suspect" (in reality just questioned as an arguido) may have unwittingly influenced people's memories, as I've already mentioned on a different thread.
Someone outside the group might have mixed up Murat with David Payne, for example (although he wouldn't have been translating).
Others may have mixed him up with John Hill. He required an interpreter for his PJ interview, so wasn't fluent in Portuguese, however as a manager, I would have thought he'd have a good enough working knowledge of the language to attempt to interpret for the GNR that evening (if indeed he tried to).
I can't think of a plausible reason why Murat would deny helping to translate that evening if he had been. On the contrary, I would have found it suspicious if he'd insisted that he HAD been there, but no one saw him.