How does transformation work? Is it just an illusion or is the meditator actually transforming the biology of their body. For example, if someone transforms himself into a Yakkha, would he also gain super strength, or is it just an illusion like putting on a cosplay.
In order to fly, should the meditator use the earth or wind kasina? If he uses the earth kasina, how does he travel in the air while standing? If a meditator fly or teleport to another country without paying the visa’s fee, does it break the precepts?
For mind-reading, does the meditator know exactly what thoughts someone is thinking? Does the meditator hear someone’s inner thoughts or do they just know whether someone is happy, sad, or angry, and not exactly what thought they are thinking?
I think, in order to attain psychic powers, one would need to practice the 14 ways(as mentioned in the Visudimagga) very strictly and intensely in all 3 postures 24/7. I’d say one would also need to have memorized the explanation on attaining jhanas and psychic powers as explained in the Visuddhimagga because that will make things easier.
I remember reading that the ascetic Sumedha practiced without lying down at all and attained physics powers within 7 days. He was putting in a very strong effort. He was already very well learned and knowledgeable in the Vedas. The Vedas of his time might had included how to attain jhanas and psychic powers. So this shows that even someone who was ready to receive a definite prophecy needed to be very knowledgeable and put in strong effort to attain psychic powers.