Started a new toon with 1.3,
Did a bit of main quest, around about where you become thane of whiterun.
Bought the whiterun house, dumped all my excess baggage in chest upstairs.
Went and followed the stormcloak quest line, (wasn't happy about having to attack my "home" city btw....)
Came back to check on the house after the stormcloak vs whiterun quest, all good. (although the door was coming up as "requires a key")
Went up to the castle to see what had changed
New Jarl, who wanted to appoint a thane... (but i thought I was already a Thane)
Tells me to go buy a house and help 5 locals... (new thane lives under a rock, seeing as I already own a house and saved the city from the dragon)
Auto-appointed Thane through RPL (recognition of prior L337-ness)
Back too house, HAVE TWO HOUSECARLS .... wtf... meh
Back to castle for home decoration...
The Jarls missus wont speak to me and the Jarl doesn't have anything to mention about the decorations... <- Bug?

So now I'm the duplicate Thane of whiterun with two housecarls in an empty house (btw, do they share that single bed?)

The steward is a man named Brill. Speak to him, he'll set you up with decorations.

Does brill ever show up int he castle?

Yes, he should be mimicing the previous steward's activities.

If he's not there and you know for certain (check the throne area around 10 AM-ish and he should be there), something probably happened to him or the game glitched up.