Balrog and servants of Sauron

[the phantom]

It also has always puzzled me that so many orcs could be found so far from Mordor as they would have had to cross Rohan and other friendly areas.

The orcs didn't have to come from Mordor. There's a mountain called Gundabad (sp? don't have my book handy) that is located near the northern end of the Misty Mountains and for quite a while it was sort of an orc capitol city. There've been orcs in that part of ME for quite a while and they can replenish their own population without sending out orders for more uglies from the Mordor orc factory.

How do the orcs in the now deserted Moria survive?

Well, they probably fished in the deep pools (remember that the Goblin King in The Hobbit enjoyed fish from Gollum's pool). And also I would be surprised if there wasn't a little cannibalism going on amongst the orcs.