Q5) How does one decide the best form of discipline for a child?
The best form of discipline is one in which your child’s behaviour is changed voluntarily. Discipline is not punishment. Discipline is helping a child find solution for a problematic behaviour. Punishment is making a child suffer for having a problem behaviour.
Try out different ideas and see what works with your child. In general, once a child can be reasoned with, physical punishment is less helpful. Uncontrolled use of physical punishment can be emotionally damaging. Being calm and talking it out with your child and even letting your child generate his own solutions is certainly more helpful as it encourages collaboration instead of building resistance.