On this site, there are questions that are often not directly answered by anything in canon materials. Sometimes answers need to be speculative. My question is, have there been any speculative accepted answers (based on the best available evidence at the time) that have been used in subsequent official (i.e. not fan-fiction) works? If so, what was the first instance of this?
I know this might be a bit opinion based, so I'll constrain it to any instances where this site has been specifically acknowledged or contacted regarding this.