What were the requirements for receiving PMC?

Declaring an early interest. That is mainly it.

Were 499,000 PMC given to just a handful of people?

Quite a many handfuls, who them themselves gave it to many others.

How much PMC did each developer receive?

0. The dev gave them all away.

Are there any left for regular users?

If you mean of the initial coins? No. They are now in the hands of users, the market, and so on. The coin has become valuable now, so giving it away would be like giving people free BTC. It would defeat the point. There are still promotional giveaways taking place, so you can still get coins for nothing, but the initial phase of the distribution ended some time ago.