You don't need to reason about C's pointers to consider its Turing Complete. That it allows arbitrary storage, it has conditionals and allows full looping (either unbounded loops or full recursion) is enough. That is, a language that had C's semantics sans pointers would still be Turing Complete.
I actually pondered on this for a long time, and I haven't come to a conclusion. I cannot, however, counter any of your arguments, as I thought some of the same things myself.
