1. What do you mean by Battleforce? If you mean Troop choice, then no, you need a minimum of two. Furthermore, at 1,000 points, a SINGLE monolith MIGHT be justified...
2. As previously stated, whatever you enjoy wearing as the flesh of your enemies. If you have played against Ork players alot, paint 'em green to taunt those thumpin' Ork boyz.
3. Previous posts have hinted towards it, but more than anything all you need to remember is that ressurection orbs are as essential to necrons as bolters are to Space Marines: you could go without them, but you'd be damn foolish to do so.
4. They are fairly straight forward, although ultimately Space Marines are the best for 40k n00bs, as the figurines are cheaper and the strategims are generally more straight forward. With Necrons you have to keep an eye on your Necron percentages for the "Phase Out" rule, keep them in formation within the ressurection orb's effects, utilize their poor list of troop upgrades correctly, etc., all while resisting the urge to pump the Necron Lord full of goodies.
5. Since the Necrons aren't doing so hot in the tournament, probably not.
Now, a side note. Never. Ever. EVER. Field three monoliths. It's a waste of points, it's cheap, it's annnoying, and your Necron population won't have to be killed nearly as much to phase out your army. Just say NO... to three monoliths.