The fidelity that musical biopics tend to have towards the chronology of public record – especially when the subject or their families are still alive, and liable to kick up a fuss over films playing fast and loose with their story – makes it difficult to know what parts to keep and what do ditch. Live fast, die young stories are good because you can fit everything in to a tight arc of glamourous decline. Complex, sprawling careers are more challenging, but can be can be reduced to a single period for convenience. Others take a more experimental approach, like Todd…