Hey, far be it for a n00b to the forums to wade in in a discussion, but I think this quote from
wikipedia.org/wiki/Ganon might prove useful here:
For the development of Ocarina of Time, Ganon was conceived by character designer Satoru Takizawa... Since Ganon was a pig, Takizawa decided that Ganondorf should turn into a pig at the end of the game despite the opinions of other staff members. He decided on making Ganon a beast “with the feeling of a pig†to reference A Link to the Past.
So, I'd say not a pig in Oot then.
For my money, I'd call him a sort of chimera, being no one particular creature, but a mix of a few; the face especially looks to be that of a bat with horns (in the manga, he REALLY looks like a bat with horns IMO,) cloven hooves, and a lizard/dinosaur tail (perhaps leading to the dinolfos comparison/confusion.)
Also, just like to add this is my favorite form of G in any of the tloz games, and would LOVE to see him sprited!
Rock!