Sorry I've not been on here much.
For landscape and seascape, the northwest coat is really nice so Birsay is a great place to be. You can try Yesnaby, the Brough of Birsay and the Bay of Skail there which are great. Brough of Birsay is also the best for northern light.
For seals it's got to be a beach called Windwick on the east coast of South Ronaldsay, it seems to have the later seal pups there, as Christmas new year is pushing it a bit late really. But I saw them there at Christmas for sure when I had some family up. We tried first the west coast of South Ronaldsay (burwick to sandwick) but they were all gone there.
If you do go to windwick half way down the road (from the main road to windwick itself) there is a tiny wood called Olaf wood that is really great for birds.
Otter, you'd have to be lucky but last winter it's during the cold snap that the otters was the most seen. Often near brig o wait. I have seen otters only twice. You have to be lucky. This is near the ring of brodgar, stone of stenness and maeshowe and there is often common seals in the lochs there.
Archaeology I am not sure of opening at this time of the year but I love Maeshowe and its got a roof, so perfect for a cold day, Skara brae.
History near Birsay there is a great mill to visit, the barony mill which still works and makes flour. The museum in Kirkwall is worth looking at just across from the cathedral.
RSPB hides to look for "the loons", "cottascarth". I see Hen Harrier pretty often while driving but actually never been when and where I wanted to see them!
Again if you have some question just fire them up. I can try to help.
Anyhow, you won't get bore in Orkney there is a lot too see for any kind of taste.