Norfolk Island Pine is not a commonly used interior plant in the professional trade because they are not an easy plant; in 30 years I've only had 2. Also, I suspect, there's a lot of individual variation - in other words, you might try several times to grow one, and fail miserably, then suddenly, in the same conditions under which all the others died, you'll find one that perks along happy as you please. That being said, let me share with you my experience.
The first NIP I ever saw in office was by a window in a NYC office building, dirty and half shaded by venetian blinds. It had grown tall enough to hit the ceiling, and it must have been five feet in diameter. It was absolutely gorgeous. It was never repotted, fertilized maybe once a year, and watered only when it was NEARLY dry all the way to the bottom of the pot. The 2nd NIP was in a much larger spot by a long window wall where it got super light. It was watered when the soil was slightly damp in the bottom of the pot, and was fertilized 3 times a year. It did beautifully.
From this I hope you will take a few bits of info that might help you with your plant. 1st, a plant in lower light will take less water, and will need to have its soil better aerated between waterings. You will need to check the soil moisture all the way to the bottom of the pot, not just on the top couple of inches. You can do this by using a soil probe that will reach this deep - http://www.youtube.com/watch?v=Tf-8InSamYQ is a short video that will explain the use of probes.
2nd thing is light; a north window might be considered bright indirect if it is unobstructed by trees or curtains, but in any case it should be sufficient if you don't let the soil stay too wet.
3rd, humidity. Any humidity you can add from an aquarium, or even a humidifier, will be all to the good, but not necessary. No one ever humidified the NIP's I've told you about, they thrived in the office air right along with the people. BTW, misting once a week would be absolutely useless; also misting every day, or even every hour. The mist droplets disappear into the ambient air without affecting the humidity for more than a few minutes. Good luck.