I've never heard the term 'farewell list'.
My experience is that you don't have to tell many people.
If you want people to know, you tell someone and ask them to tell X, Y, and Z.
If you want the news to get out, it can cascade out quite quickly.
You tell your Line Manager, and ask them to share it with the team.
You tell your Mum and ask her to tell the family.
You tell one friend and ask her to let A, B, C and D know
You tell someone at your hobby and ask them to let the others know.
If you have dc, then you get your partner to let the schools know.
If this is a question about how many people would want to come to your funeral should the worst happen, I think you'd be surprised. When someone dies very young, a lot of people tend to make the effort to come.
But, if that is what you are asking, I've got a lot more than 14 people just in terms of family, before you get on to others who would need to know, or who would want to come to celebrate my life.
HOWEVER
I hope your biopsy result is good news when it comes and this is just a late night, theoretical musing.
It is a time you tend to think of the 'what ifs...'