[expat2]

Interesting material.
I am a researcher but neither a theologian nor a linguist and I seem to have followed Fitzmyer's path in my thoughts produced by the posting and registered on this thread.
As far as the petros/petra issue is concerned, the Matthean passage would not be the first writing to have a typo in it nor the first piece to be carelessly written/translated. You can see it all the time in our present day,

I am reluctant to accept consensus of researchers without question. Many years ago, I lived with several geology students and had the temerity to mention to them that I believed in Continental Drift. I was scorned heartily for that because at that time the world's Geology professors had decided that that was akin to flat-earth belief.
Of course, only a few years later it became a respectable and universal position.

[Greetings_Puny_Humans]

As far as the petros/petra issue is concerned, the Matthean passage would not be the first writing to have a typo in it nor the first piece to be carelessly written/translated.

A typo? That's ridiculous. Are there any manuscripts in existance that do not have the "typo"? The testimony from the Church Fathers does quite well in also confirming the proper reading of the verse.