Shticky Guy – I think the Eruv Rav (and probably also the geirim) set up camp out of the ???? ?????.
I asked one of my Rabeim, and he told me your tirutz (possibly from the Rambam; alternatively it could have been the Raavad on Toras Cohanim). Another answer is (like a wrote above) that even after ??? ???? if the father in not Jewish, then even if the mother is, the child will not be Jewish (contary to common belief). The ??? ???? brings a proof from this ???.
Another ????? was that we are saying he was ????? at ?? ???? just like everybody else; the ????? is that he came even though he father was an Egyptian, the ???? is informing us that he wasn’t because he came with his mother to convert.