Now for the questions...
I'll do my best... though I'm just a beginner at all this. I'm sure others will correct me.
You said, (earlier) “…that which is changing, …” So isn’t the “that” the “self” even though it changes?This is one of those cases where language doesn't cut it. "That" was the best word I could think of. I don't think "self" is normally thought of something that changes. It is more the platonic form that is the essence of the object. I see no convincing evidence that there is this thing which carries on throughout our lives.
Buddhists speak of the relative and the absolute. Here is one of many discourses on the subject. The relative is the world of Sansara and the absolute is the world of Nirvana. The relative is supported by our senses. It is the "Cyclic existence, the beginningless and endless wheel of rebirth. The world, the realm of desire." The absolute is supported by enlightening experiences. It is "The ineffable ultimate in which one has attained disinterested wisdom and compassion." (Quotes from http://sansara-nirvana.tripod.com/) The challenge is to hold both of these "worlds" in your mind simultaneously. We need the relative to navigate, and we need the absolute to relieve suffering. The acrobat trusts his skill, but is prepared, should he fall, to not land on his head.
I know that you said that your parents were different to you than to each of your siblings. I get that. I know that I am different to each person I come into contact with because my response is based on how everything about me relates to everything about that other person.For whatever reason, we believe many things that are not the way things are. In what sense are you the same person? You've heard that every seven years your atoms are exchanged with new molecules. Click on the link to read of Rudolf Steiner's idea that not only do the atoms change but our personality changes as well.
However to me, I am still the same person, I have the same sense of self now as I did when I was 5.
When I was a small child, at about 5, I had an experience that was very clear. I had an instantaneous sense or awareness that I existed. It was almost a physical sensation. I am. I exist. And with it, I was also aware that it was different from not existing. But the not existing did not lack an awareness of not existing. I think this is why I asked about this.Is this like Descartes, "I think therefore I am"?
If the “self” is consciousness, then consciousness though evolving, is still consciousness, the same consciousness, which upon death is also reborn.It is not the same if it is changing. I'm today different from you today. You today are different from you yesterday. But as to rebirth, I have no idea what happens upon death other than how the effect we have had on people continues.
Also you said, that though “Zen people aren’t very concerned with rebirth at death…[and]…few say you are not a Buddhist if you don’t believe in it.
So isn’t the real point is not whether we are reborn or not or whether we create good or bad karma, but whether we live to cause less or more suffering.We don't "cause" suffering. We can cause pain, but suffering is more about how we respond to pain.
And wouldn’t it follow that to desire to live to cause less suffering, that we must not only experience suffering in our own “self” but also to acknowledge the self in each of us in order to care whether one’s suffering is eased?Sounds like you are talking about compassion. But imagine that you aren't a separate being but interconnected with all things. Your suffering continues until all suffering ends. Compassion doesn't end suffering as much as it eases the pain. What a person does with their pain is up to them.