Well, if we are to be correct, the country should not be Norway but Norge. But since I sincerely doubt there was a country actually called Norge or Norway in the year 450 the spelling really don't matter.
At least in Sweden there was not a united country that early, there were local chiefs and what they themself called their region we will never know exactly.
If we are to be really, really correct he was never called Halfdan the old, in old norse he would be Hálfdanr gamli or Hálfdanr inn gamli.
Snorre Sturlasson who wrote these sagas/legends is said to have lived abt 1179-1241 and he writes about persons several hundred years before him.
Just add the templates for Uncertain Existence and Norse Mythology and don't bother with any spelling is my advice. Alternatively, you could go all in, delete all connections to family members and only link to them in the biography, telling the which Norse legend he is included in and who the author of the saga/legend is. Example profile https://www.wikitree.com/wiki/Arimathea-11
