If you don't mind my taking a snap at it... I don't ship it either, but let's see...

who cooks normally? - Luna. Draco’s not quite of the ‘woman make me a sandwich’ line, but after a Malfoy upbringing with House Elves, he’s a little rubbish at cooking, himself.
how often do they fight? - Frequently, but about silly things. Hogwarts House wars. The TV channel. Luna isn't one to hold a grudge and Draco appreciates how the past is rarely brought up.
what do they do when they’re away from each other? Draco mopes. When she’s away, it’s on Quibbler business, so Luna is typically up to all manner of wonderful things and it doesn’t occur to her that Draco wouldn’t be. More likely he spends his time, I’d say in politics, cutting through the red tape to surpass his family name, and is too busy to be lonely. The reunions are nice, though.
nicknames for each other? Draco sometimes slips up and calls Luna ‘Lovegood’, which she doesn’t mind so much, but he does twitch a little when she brings out her latest string of gushy, cavity-inducing ( ... )

River/Eleven ( ... )

This is cute. :D

I would also think Gwen would be the harsher swearer of the two. XD