Greenland sits further north magnetically than anywhere else here bar Svalbard: Kangerlussuaq at 71.1°N and Ilulissat at 73.4°N, both with a required Kp of 0. Kangerlussuaq is inland at the head of a long fjord, which makes it markedly drier than the coast. Both peak in October, earlier than the Scandinavian destinations.
Required Kp is calibrated from magnetic latitude, not the latitude on a map, which is why two places at the same map position can need very different activity.
None to speak of. Both Kangerlussuaq and Ilulissat have a threshold of Kp 0, from magnetic latitudes of 71.1°N and 73.4°N. At those latitudes the oval is overhead or close to it whenever the sky is dark and clear.
September to March at Kangerlussuaq and September to April at Ilulissat, and our month-by-month curves put the strongest month at October for both, earlier than the Scandinavian destinations, which peak nearer March.
Kangerlussuaq sits inland at the head of a long fjord and is noticeably drier than the coast, which is the single biggest factor once the required Kp is already zero at both. Ilulissat is further north and has the longer season of the two.