Hello again all and sorry for the rather long awaited answer to things, I had to go through the trouble of getting a new computer. I REALLY appreciate all the advice and suggestions on here, especially since I had originally expected a lot of yes or no answers!
As it stands they've been coming around a bit more often, though still having missed a couple of our recent games, and I've had a talk with them in the meantime. Unfortunately I still don't feel comfortable running the game without them now more because of how the plot is going, the campaign may in fact be done (after roughly 2 years) within the next month or so and I don't feel it would be fair to have them miss it, however taking the advice from several people on here and talking it out with the players who do show up I've started a much easier to balance and simpler style game with just them so when the other 2 don't show, they just get to be the stars of their own side game, which so far has made everyone rather satisfied.
As it stands to be still annoying when they don't show, I admit I was jumping the gun a bit at the idea of killing the characters off from the other players annoyance getting to me after so long, and just told them that if they DO miss is more then is reasonable, I'll have to player there characters for them and they'll miss the ending, mostly because if not them I'd need to write up two more guys that somehow remotely fit the rather special situation going on in game, and that's tiring sometimes lol.
Since the game is supposed to have a 'sequel' in the same world using the main characters descendants though, I've been talking regularly with them to try and find a better schedule to work around, I'd love to find one or two new players to just avoid this situation again in the first place of course, though I'm not much the type to make friends easy (yeah antisocial DM, that can't cause issues right?...), but maybe one of the group knows some people that wouldn't mind pouring over pages of established story and world to make something
Again though seriously, thanks guys, this was a lot of help and has some great ideas for more then just the situation I came for help on- side note I labeled the thread Pathfinder on reflex cause that's the game we're playing, buuuut....yeah it probably should have gone in a more broad topic XD