Actually if you name him "Red XIII" or anything else, he still says that "Nanaki is Nanaki" as if to mean "Whaddya mean, who is he?".
What is amusing, however, is in Rocket Town when he introduces himself to Shera; "Nanaki, also known as Nanaki."
Anyways, I remember the ol' 1/35 General Aeris revival rumour.
Now time for a non-FF7 rumour as there's only been one genuine one and a bunch more that were sarcastic!
FF9, recruiting a hidden character named "Salamander". Poor fools, not realising that was Amarant's other name.
I was also told that when Dagger summoned Ark, she didn't disappear, and she hopped on to ride it once it appeared.