Amanaki, I hope you don't mind, but I modified the format of your questions for my own purposes. I don't think I changed the intent or meaning of any of your questions. If you think I did, feel free to complain.
Regarding #3: My understanding of what a Buddha is, begins with my understanding of who, as far as I know, the first Buddha was. As far as I know, the first Buddha was:
- Siddhāṛtha Gautamā, c. 563/480 – c. 483/400 BCE
I am comfortable believing that Siddhartha was an actual person, as real as you and I are. Can I prove that he existed? No, and I have no interest or intention to try to prove that he existed.
My understanding is that Siddhartha abandoned his wife and kid(s) when he was about 29 years old and proceeded to think and contemplate his way to "enlightenment". He left behind a number of teachings, but I don't remember hearing that he ever left written statements or instructions. My impression is that he was primarily interested in addressing "rebirth" and "suffering".
I read (at Wikipedia,
Gautama Buddha - Wikipedia) "Accounts of his life, discourses and
monastic rules are believed by Buddhists to have been summarized after his death and memorized by his followers. Various collections of teachings attributed to him were passed down by
oral tradition and
first committed to writing about 400 years later."
From what I can tell, his current state, regardless what that state is, eliminates his ability to do anything for or on behalf of or to communicate personally with any living human being.
IMO, "a Buddha", on the other hand, is someone who has theoretically achieved what Siddhartha purportedly achieved: an end to an assumed cycle of rebirth and an end to suffering, nothing more or less.
Although I am sure that there are folks who add beliefs and opinions to that, I'm not really interested in expanding my understanding of Siddhartha, enlightenment/Buddhahood, or Buddhism beyond what I have written above.
(To be continued)