Here's a link to a pretty good cider-for-newbies site:
What my research has told me is you didn't even really need the campden tabs for the pasteurized cider - all that does is prevent wild yeast from stepping in and taking over.
I literally just dumped my cider into the carboy, added a small amount of honey, swirled the heck out of it all, and pitched the yeast (used a white labs English cider strain).
Took about 3 weeks for it to get to 1.000 when I moved it into secondary containers to condition (some yeast produces a bit of sulfur, which ages out just fine but you have to give it some time).
As far as spicing goes, I would wait until the primary fermentation is done, and you can move it to a secondary (or keg) for conditioning. My understanding is that adding spice to the primary can create an effect that is more bitter or too overpowering.
Whole spice is better than ground - you don't want to have cinnamon powder floaties in your cider.
Most cider (if not all) ferments "dry" - in that the sugar gets gobbled up by the yeast. What you're left with depends on the yeast you used, fermentation temps, whether or not you used honey, sugar, etc. (and that would be more in the category of describing the type of wine you get from different grapes and yeast).
In the case of the cider I did, after 3 weeks I put about a half gallon of it into some fliptop bottles and added some apple juice concentrate for carbonation. This will be "dry" (like a dry wine) vs. "sweet" (like a Woodchuck or Magners). The 2 gallons I have left will end up getting spiced with some cinnamon and vanilla, then bottled with some lactose to bring out the fruit and add some sweetness.
The idea of back sweetening is entirely based on preference, and whether or not you have the ability to force carb (if you can force carb in a keg, then you could use sulfites to kill the yeast and then sweeten it to taste).
You definitely want your cider to get to 1.000 or 1.099 before bottling unless you plan on force carbing and using some method to kill the yeast. Otherwise you could end up with bottle bombs at some point down the road.
With cider, all signs point to "Time is your best friend. Patience is a close second"