Translation:The dress has exactly the right color.
I would put the emphasis on Akkurat when saying this, not needing a definitive. If you want to have a definitive word "Kjolen har akkurat den riktige fargen" for me that turns the meaning over from a (perfect) dress with a perfect (unspecified) color (it's just right!!! I want it!!)), and in to a dress with a color that perfectly matches some other colored item I have, that color
From what I've learnt so far, 'accurate' isn't a translation of 'akkurat' in these contexts.
In English, accurate means exact but usually in a mathematical or technical sense, or similar. It is an accurate map. It is an accurate calculation. It is an accurate weather forecast. And so on.
The only way I'd use it for a colour is to say one colour is an accurate match to another (eg, when trying to match paint samples).
Depending on context, yes. In the dress example they are interchangeable.
Nøyaktig (from German) can mean precise, accurate, exact. And it can be an adverb (precisely, just). Akkurat (from latin) can mean precise, exact. And it has a monetary value. Har du nok penger til bussen? Ja, jeg har akkurat. Do you have enough money for the buss fare? Yes, I have exactly the right amount (not more, not less)