That's a pretty slick lookin' tank! I have plans for that type of nano cube for my desk one of these days.
The MJ600 should suffice - but DO remember that powerheads suffer under head, so the higher the fuge is, the less flow you'll get. Worst case I guess is you pick up a MJ1200 for 35 bucks.
You can use either flex tubing or PVC. Both make one end of the job easy and the other horribly difficult.
If you use flex tubing, you have a problem connecting it to the bulkhead. I'm pushing water into my fuge using an Aquaclear 802 powerhead. The output of the powerhead is flex tubing (clear vinyl stuff), and it runs to a 1/2" threaded bulkhead I picked up at J&L. Vinyl hose has the nice property of holding a grotesquely larger shape if you work it... Hold it in boiling water for a few seconds and then use a couple pairs of pliers to yank it wide open.. Holding it there, throw it in some ice water for a few seconds. If it's cooled enough, the hose will stay extra large (I think you can double the radius, though I've never had the strength and endurance to get it that wide). Now it can be slipped over the bulkhead (if the threaded bit sticks *out* from the fuge). Submerge the hose/bulkhead in boiling water again and the hose will shrivel back to its original size. Let it cool and I can almost guarantee that you'll never, ever get that hose off.
The other option is PVC. You can get regular white PVC from Rona/HD and cement it to the buklhead.. Nice fit. Except now connecting the PVC to the powerhead becomes a pain in the rear. I suppose you could also meet flex tube and PVC halfway up...
But that assumes you're using a bulkhead for the input.. Which I actually strongly recommend. Just having a hose come up and sit inside adds another potential fail point (suppose whatever is holding the hose in slips out) - you can do some fancy footwork to avoid that, but personally I don't know if I'd like the look of it.
For the return, you can actually do something neat (just thought of this).. Might as well do a PVC return down into the tank.. Instead of just letting the water fall in (or to the side if you add a PVC elbow), check out King Ed. They've got these rotating attachments you can connect to any powerhead, similar to a PowerSweep. I wish I remembered the company name right now.. Starts with an 'H'.. 5 letters.. If you walk in it's on a small endcap at the back of the dry fish food aisle beside all the light tubes. It was about $15 and had a pretty good review on RC a while back. What it does it constantly rotates 360 degrees as long as water is flowing through it, so you'll get a mini wave device instead of a steady current.
Are you a light sleeper? I tend to be a pretty heavy sleeper, but some sounds drive me nuts and prevent me from falling asleep (ie. when one of my Aquaclear powerheads clogs up it makes this horrible grinding/whining sound). The surge and flow from it, believe it or not, are actually rather soothing once you get used to it after a couple of nights. You might find that the water moving through the fuge circuit is actually relaxing (if you can even hear it).