Welcome. However, your original point - that recollections may vary, to borrow a useful line from Buckingham Palace - is worth holding in mind when reading memoirs and also when reading (and, one hopes, writing) biographies. It can be tough, because sometimes the best raconteurs are the least reliable.
This has a special application when it comes to ballet, because writers or ballet masters/mistresses who are trying to reconstruct how a ballet was first made and how it's changed over time frequently have to contend with differing recollections. I found a good discussion on an old BA thread:
Oral history