The snow accumulates. The amount of snow there would be varies from year to year though.
Yes, different areas get different temps, even within Troms. The closer you are to the coast the higher the chance that the temps will be mild and the snow less reliable because of the Gulf Stream. You can also risk that you would not be above the cloud deck (if raining or snowing) to be able to see the Polar lights. Inland tends to be colder and clearer.
I would recommend checking the site met.no, which is the norwegian weather service's website.