Precisely why I included the adjective, "well-functioning". . . .

I would add that basically everything you list is why there exists in human cultures a general disapproval of suicide, because people may feel bad in the situations you list, but suicide is not a good answer; in most cases the person's feelings will change and they will be glad they chose not to kill themselves. Deciding to die for reasons like those listed is not generally considered "dying with dignity"; it's a tragic case of people becoming overwhelmed by feeling to their own detriment.