I think it was November 22 that I did the bus excursion, too, but we were less fortunate than you. Even driving all the way to Sweden, we didn't get to see the Lights.
I didn't find it particularly cold, but I'm a northerner and we're well known for scoffing at coats.
There were facilities on the bus. We didn't get hot chocolate but we did get a nice fruity drink, almost like a non-alcoholic mulled wine, and a chocolate biscuit.
Because ours was the Cunard excursion, there were no issues with getting back on board.
I'm another who wouldn't bother with the Cunard bus again. Then again, by this stage, I've accepted that I'm just never going to see the Northern Lights, because I keep sleeping through the blooming things! (But I did see the Southern Lights while sailing a brig from Tasmania, so that was nice.)