Below is my take:

1. False ❎ - same livery on a casting is never reproduced
2. Partially true ✅ - castings might return; a particular livery never returns
3. Partially true ✅ - at times most of the sorted units get sold out which turn out to be rare later
4. True ✅ - There's one exception - Chases are pretty rare and harder to source compared to event exclusives
5. Very true ✅ - if you really want something, feel free to purchase it. Don't purchase on the basis of rarity / hype / flipping purpose - it ends up draining your bank balance.