Genuine sounds a bit odd here. When used to describe people, genuine normally relates to their personality, rather than their existence; so the implied opposite to genuine is not fictitious/literary, but rather dishonest/deceitful. “The genuine pioneer’s story” makes it sound like it’s the story of a pioneer with a very pure and honest disposition (rather than the story of a pioneer who was a liar and a cheat).
When applied to something like a story, genuine normally pertains to the objective and verified veracity of something; its opposite is something along the lines of counterfeit. “The genuine pioneer story” makes it sound like this is a verified, non-counterfeit story about pioneers, the implication being that there is another, unverified and false story somewhere as well.
More appropriate adjectives would be real or true. While both of these are also antonyms of fake, false, they are commonly used to separate real-world characters and stories from fictitious ones (and they certainly don’t say anything about a person’s personality or disposition). For example, when a movie is said to be “based on a true story”, that doesn’t imply that there is a false story going around also, just that the movie is based on events that took place in the real, non-fictitious world (even the real world uses real here). Indeed, this Visit Östergötland page uses true in the title for a launching event of the Andrew & Elsa CD in July.
In addition, it sounds a bit unnecessary and not very ‘title idiomatic’ to have story as part of the title in English. This is quite language-dependent (and perhaps also purely subjective), but while in Swedish, the title Andrew och Elsa – den äkta pionjärhistorien sounds quite natural as the title of a “musical audio book” (as they call it), I think it would follow the general tendencies of titles in English better to simply call the English version Andrew and Elsa: the true pioneers.
The explanatory subtitle could then include the story bit: “The story of the people who inspired the characters in the renowned Emigrant novels” or something like that.