Depends on how long you bulk age. I've aged a cider for 6 months and was still able to bottle condition. If you let it sit for more than a year, you will have to add yeast back in to bottle condition. If you are bottle conditioning, you will always end up with sediment. Its true, most of the bigger commercial cider makers filter and force carbonate.
Not sure about ciders, but a lot of microbrewers (beer) like Sierra Nevada actually filter out all of the yeast, then add back in a very exact amount of sugar/yeast to bottle condition. This would be pretty hard to replicate on the homebrewing level though.
As for the campden, are you pressing your own juice, using juice bought from an orchard, or buying store bought juice. If you press your own, you should use campden to knock out the wild yeast.
This is a good start to know how much campden to add. Click on "Part 3 Juicing and Fermentation", then scroll down to "Sulphur Dioxide".
If you are buying store juice, no need to use campden. Its already pasteurized. I'm not sure of the laws in Chile, but here in the US, all of the orchards that produce unfiltered juice and sell it (yea, its called cider here although its not fermented) are required to pasteurize. If you are lucky, you can get a mill to set aside some juice for you.