Kind of based on the fact that as kids, my siblings and I used to jump and dance on our parents' bed whenever we heard music. Plus, with a hint of backstory on these characters:
These four were a part of an experiment that took place in the University of Xenomorphic Relations and Health, which involved raising separate species a siblings. Two of these four were the results of two other experiments as well, the Shofixti girl Lala(from an experiment to produce a breed of Shofixti who would age significantly slower than the normal variety, which ended up being successful, but not without its share of consequences), and Melnorme Indigo(who was the first Melnorme born through in-vitro fertilization, his surrogate mother didn't wish to keep him after finding out that he was produced from a sample that was NOT the surrogate's).
Alana, Brunkel, Lala and Indigo grew very attached to eachother once Indigo was inducted into the family and all have pleasant memories of their childhoods, this memory being the one that stuck to them for years to come, even after separating and growing up.