Hey @ripper234, congrats on your first post after a year 
A) There are exactly 430 million MaidSafecoin that were sold in the pre-sale, there will never be any more.
B) There can be up to 4.3 billion Safecoin (same link), but they are replenished in the network, so it’s a bit quirky to answer. That means once a safecoin is generated, it doesn’t necessarily exist forever, because when it’s “spent” the network marks that safecoin’s id from “alive/valid” to “dead/not valid, but can be regenerated through farming”. So if there are 1 billion safecoins, there could be more generated, or if there is a lot of spending across the network, it may drop to 500 million (it’s attached to the network’s farming rate and health).
I’m going to call on @dirvine to answer how POR works, because I’ve read discussion that it could be an alternate to Safecoin, but I’m not entirely sure what the current thinking is on it.