Series of celebrations
If you can tell on which date of 2019 these conversations most plausibly happened and put them in the order of time, you should be able to unlock the Key. Don't overthink this. If the dates are Jan 01 Feb 02 and March 03, then the sequence you're looking for is 010102020303. If the conversation is about a sequence of dates, use the first day in the sequence. Happy holidays!