“This I agree, if it is unique, it is less likely to be made up by someone or groups of people”
Tipitaka contains different layers of detailed and self-consistent explanations of mental phenomena. We must keep in mind that no other religion, philosophy or even modern science describes the conscious experience to such depth.
“I first came upon this line of thinking when I did a search and did not find strong evidence pointing to the first arahant council”
Not sure what counts as “strong evidence” to you, but the description of the first Buddhist Council is in the Tipitaka itself. Read, Pañcasatikakkhandhaka
“What we have now do not strongly point to whether the contents of the tipitaka are factual or not, eg some would argue if they are made up or exaggerated, especially the mythical phenomenons, eg talking to devas, pretas. Some would also argue if they were made up. Of course, if we were to take the assumption that they were written by arahants, then they should no have lied as well when creating the tipitaka.”
OK, here’s how I approach it. There are essentially 3 ways of determining whether something is “factual” or not:
- Analyzing the self-consistency
- Examining the consistency with observed facts
- Using one’s direct experience
To gain confidence in a teaching, we can use #1 and 2. For example, scientists can’t “see” electrons directly but we are confident that they exist. This is because those models are consistent with observations. Using the same approach in Dhamma, even though we can’t directly see the 29 other realms, we can be confident that they exist. The goal is to treat the fundamental concepts like Rebirth, Laws of Kamma, etc. like foundations/axioms and go through the explanations (based on those axioms) and see if they lead to logical conclusions.
But of course, an even better (the most reliable) way of being confident is by seeing the truth for yourself (#3). Before the sotapanna anugami stage, one experiences the cooling down effect (Niramisa Sukha). An anagami does not crave anything in the sensual realms (kama loka). You can make them watch adult movies, but they won’t generate a trace of lust. Someone with 4th Jhana can willfully come out of their bodies. If they have abhinna powers, they can recall past lives too. Tipitaka recommends walking the path in stages, so until one develops such abilities like seeing beings in other realms (for example), we must rely on #1 and 2 and continue our practice.