an alternative which help strength, minor plaque, whitening naturally and everything you can think of is by adding 2 drops of tea tree oil to your toothpaste when brushing your teeth, you dont necessarily need mouthwash then but whatever takes your fancy
Tooth paste usually contains enough salt content that is required for your teeth to maintain their strength . There is no need for you to add salt separately .
it may help whiten them if you dip your brush in warm salt water, i dont think it will help strengthen enamel
No - it will do the opposite.
Salt is abrasive - it will wear down your enamel.