Okay, a quick note, the endings on 'zawj' and 'jadiid' should either both be -u(n) or -i(n), not one of each. Right now it sounds like "zawju jadiidin mumtaaz". Whatever ending goes on 'zawj', that same ending should go on the other words (although it's optional in the last word of the phrase, here 'mumtaaz'). These endings are used to show case relationships (either nominative, accusative, or genitive/dative), and definiteness (either definite or indefinite).
It's a part of a sentence. It is neutrally diacritizied on purpose because it could be in any of those grammatical cases, which it currently isn't because it isn't in a sentence that would put it in a grammatical case.
I put "A new amazing husband" which I think should be marked as correct. It was marked wrong.
But in English, you have to put adjectives in a specific order. Here you can only say 'an amazing new husband'. Your version doesn't sound correct in English.
I know what you mean but this is an Arabic course, not an English course. It should really be testing someone's ability to understand the Arabic words.
Mumtaz has numerous meanings, including great and excellent, not just amazing