I have read this thread with interest, having spent almost 2 weeks on the Nordkalottleden Trail in July 2010, walking from Björkliden to Kilpisjärvi reports are here. My experiences were rain for one third of the time, sun for one third of the time and mosquitos for the other third.
I used a Stephensons 2CR Tent, which worked fine in all conditions including some very windy nights. I own a Trailstar but my main concern is mossies, which in some places (above treeline) in breezy positions were quite active. For this reason I would not use my Trailstar. After reading many of the local blogs for lapland, it seems to me that a speedmid with netting around the edges will work fine, as it will provide bug protection and if needed a bug head net can be used in adverse conditions. The speed mid is ideal in my view as well it will shed wind rain and snow. For a groundsheet I would use tyvek.
As for wet weather gear, I experienced high winds and snow, and would prefer to use a coat and overpants, not a poncho, because of the winds.
My planned trip for 2011 to the Nordkalottleden will reflect my gear choices as outlined above.