The word paret could refer to any pair. But in this specific case, since the given translation is the couple, it would be a romantic one.
The question did not imply a romantic couple, just a pair. 'The pair' should be accepted as an answer.
It is. If it wasn't accepted for you, it was probably because of an annoying bug that happens sometimes.
In croatian we also say "par" for "couple". I wonder if it's connected somehow.
They are, actually. :) Both are from Latin par, just as English "pair" is.