Is it good to track all the free traffic from social accounts?
Its always favorable to track all the traffic you are getting. In this way you can closely understand and evolve your site according to its needs.
Yes it is important, you can do it atleast every end of the month to know how effective your post are on facebook or any other social media channels.
Ya its good, generally we do SMO to optimize website in SERP and generate traffic to your website
Yes, social media is best way to get traffic on website. It is the easiest and fastest way to get traffic.