It depend on how good are those reporters. many words in mandarin have minnan equivalent for it even for those 成语。
What exactly do you mean? Would a "good" reporter use translated words from mandarin? Would the minnan equivalent for the mandarin be proper hokkien is it was just a word for word translation?
For example when they see 风调雨顺 ，they can say 年旬真好。
怨声载道＝五路哀怨。However some of the minnan equivalent are not known even by those prof who wrote the dict.