For 2. Its variable between manufacturers.
Subaru told me you can’t lease any CPOs at all. BMW/Mini I believe said only on demo/loaners. Lexus said they lease actuslly used cars.
Leasing demos/loaners can be huge savings but not always. You just have to look at the numbers and compare. Leasing new can be cheaper than new. Just depends on the incentives available, residuals, selling price, etc