I would agree with zarn abit, my understanding is all the scandanavian languages are very similar,
Danish being the simplest and Icelandic one the hard ones,
Even go too say that Dutch and German speakers can understand at least 80-90% of the Scandinavian languages!
There are words in Dutch that are exactly the same in Norweign,Danish,Icelandic and Swedish.
for example in dutch the word 'weet" means knowing is the same in Icelandic.
Swedish has alot of words similar to german and the old gothic, gaulish tounges.
Icelandic is similar to Norweign and Old Norse.
Icelandic is one of the oldest scandinavian tounges and hasnt changed since the vikings,
So to your answer I agree that yes these different languages can understand each other.
or at least get the gist!