ik,
from the rules at the beginning:
Your 3 Elders must always pursue different skills from each other with no overlap. (Don't forget that Inventing raises Handiness and Martial Arts raises Athletic.)
This means that your elders have to work on different skills. For example, if elder one learns cooking, no one else can even get one skill point in cooking.
If someone dies for whatever reason, be it old age or accidental fire, then that is where you would take their score from.
When one of your Sims is visited by Grim, the Death Flower will prevent Grim from taking their soul. As soon as Grim leaves, pause the game and note all Skill stats for the Sim. Make another Sim active. Then Shift-Click the Sim (testingcheatsenabled true needs to be active) that was visited by Grim to delete it.
About losing the death flower to a cooking opportunity, I'm not sure of sorry.
Norma