New player here and I apologize for what I'm sure will be deemed stupid questions.

I'm having a bit of trouble wrapping my head around classes vs jobs. I started as a Marauder and finished my level 30 class quest so, now, I need to start the WAR quests? ...and become a WAR? What happens to my status and progression as a MRD? ...or, do I continue on leveling as a MRD, then go back and pick up WAR later? Everything I've read indicates that MRD pretty much ceases to exist at level 30 in favor of the WAR, but there are still skills and abilities past level 30 for the MRD. If I start the WAR job, does MRD level consecutively?

Also, the "one character can be everything" concept is a bit overwhelming. I would almost prefer to, at the most, have one character with all plate dps/tank jobs, one character with all cloth dps/healer jobs, and one character with all leather dps jobs ...is this viable? Does anyone else manage their stable of characters this way? ...or does everyone simply do everything on one character? I know you can't (easily) transfer stuff back and forth, I know that alot of stuff isn't account wide, etc - that's all mostly ok with me as I'd treat each character as their own separate entity. Just wanting to get opinions on this as I'm guessing there is no real "right" answer here.

Thanks for your time and assistance.