So this dragon came out attacking, then it killed this one guy who appears to be someone important(don't remember his name), and I'm thinking maybe this guy is part of some quest that I can no longer complete because the dragon killed him. So... will he respawn because I would hate to miss out on any quest, and I'm just trying to complete every quest possible in the game because that's how I intend to play the game.
Fist fight, knife fight, gun fight, win at all cost!!!
If he's dead, then he won't be coming back ever. Only way to get him back is load a previous save. There are NPC's that can't die no matter what happens to them though. They're usually faction leaders or crucial to a key quest line, so they can't die as long as that quest isn't done yet. Maybe not even after, but I'm not sure about that.
It's not enough that we do our best; sometimes we have to do what's required. Sir Winston Churchill