1 I assume this is about Dr. Who?

2 Good guess, but no.  There's a show called Fringe, which started out as a cheap X-Files knock-off, and turned into something other than else.

How much of the back story was planned out in advance I don't know, but it actually makes sense in a way X-Files never did.  For values of sense that are perpendicular to the usual kind, but internally consistent nonetheless.

The fact that there even is a back story is a bit of a spoiler, since you don't know any of that going in to the first season.  But I think the first season would be easier to get through if you went into it knowing that things will eventually connect together; going in blind it's a bit too monster-of-the-weekish.  So it's a good spoiler.

3 The payoff for the backstory looks to be finally coming together. Although I need to catch up on the last few episodes. This appears to be the anti-Lost in terms of backstory.
Not that I watched Lost. 
Last season, the rift war pretty much kept a single storyline running through most of it. This season is a lot looser, I guess due to the ending of the rift war. Spinning variations on its own cases to  play with Olivia's memory.
The characters have always been what drew me consistently and have kept me coming back. Especially Walter.
BTW I was setting up ssh access to do some work on my wordpress setup. Was wondering if the demon is on a nonstandard port as I think I've setup the DSA keys properly.