Then obviously there was another form of communication.
This is simple logic. If the wikipedia entry was updated before the bodies were found, then it is impossible that the only communication Benoit had with the outside world was the two text messages.
That is, it is impossible, logically, for your statement that those were the only communications he had to be correct.
According to the article this same computer has made a dozen postings at Wiki dating back to mid May. Maybe someone was attempting to be funny not knowing that was what had actually happened.