[Manwe Sulimo]

The Watcher in the Water was, in fact, what attacked the Fellowship at the West Gate. It had not been there since "the beginning", seeing as how the West Gate was used frequently by the Dwarves of Khazad-dûm and the Elves of Eregion before it became Moria. Gandalf's reference to "older and more foul things" was during his reunion with the "Fellowship" in Fangorn. He was referring to creatures he saw/heard while chasing the Balrog and ascending the Endless Stair.

For earlier questions, there were *always* Orcs in the Misty Mountains. Remember, Morgoth wasn't only concerned with what happened in Belerian, but with all of Middle-earth. He doubtlessly had Orcs all throughout the Grey and Misty Mountains before the Noldor and Sindar even came east over the Blue Mountains.

The Orcs, seeing as how the Dwarves had been driven out of Khazad-dûm, plundered Dwarrowdelve and probably took the Balrog as their Lord. Remember, Balrogs are intelligent Maiar who *can* talk, and Orc racial memories probably remember Gothmog and the like.

As for food, it's a pretty generic question in Tolkien's work. The only real agriculture mentioned are in the Shire, the "southern fiefs of Gondor", and a vague reference to the "fields of Nargothrond" in an early version of "Narn î Hin Húrin". Meat couldn't possibly be supplied for so many Orcs in the caves, unless there were frequent sorties into Hollin to hunt. This leaves cannibalism, or some strange, edible creature indiginous to Moria.

Yummy.