By narrow standard, I mean... An (a)-based literal interpretation would say that creation happened twice, a (b)-based interpretation would say that where we have strong reason to believe it's metaphor it has to be metaphor. We have to interpret the Bible in some way: it's written in a language after all, not beamed directly into our brains with perfect understanding. But (b) doesn't imply that we get to sprinkle "it's a metaphor" or "that was then, this is now" wherever we want. We have to turn toward careful scholarship. The reality is that the Bible clearly contains some metaphorical language, turns of phrases, and stuff that's really lost without an in-depth understanding of the Greek/Hebrew. Some parts are clearly written to some beautiful in addition to conveying a message. So when scholars look at the language in the Bible, they do so with really careful reference to the languages of composition as understood at their time, clearly trying to separate what makes sense for translation, so the absolute minimum gets lost in multi-millennial banana phone. If I knew NT Greek I could provide careful examples, but unfortunately I'm not trained in that.

In contrast, Modernists will sprinkle metaphor wherever there's something that's slightly disagreeable, which more or less means everything goes. So it is unfair people who follow a narrow interpretation to say that there's equal "picking and choosing" going on vs. much more expansive Modernist interpretations, which clearly bend to changing societal mores to a much greater degree. A (b)-based interpretation will be much more restrictive, even though, as I said, there are multiple interpretations possible even limiting ourselves to (b), e.g. look at Luther vs. Calvin.

For your divorce question, I'd encourage you to look up modern Lutheran or Calvinist positions. I'm not familiar with their arguments so I'm too unfamiliar to recount them. A major point I've made is that there's a difference between laymen, like your relatives claiming (a), and a scholar understands (b). Like with any other expertise, it's best to defer to the experts who have actually studied the subject matter extensively.