Hi Sanchit Ji,
1)Don’t go for GST exemption. Use UPC code to list your product. Start searching for next product to add in your inventory. Work smart. You know the process now.
2)Still waiting to see your product on Amazon.in. Make it live soon. Listing seems good. Images are fine. You made some changes in that and we are happy to see that our suggestion are valuable to you. If you got time to deliver the product at your end you can make it live. As soon as FBA process is done, opt for it and you will get buy button soon. If FBA needs 1 -2 days then you can wait and starts with it.
3)About variation in electronics category, You are right that can’t be done that but this update is 1 year old. So create new listing for different colour and merge it when you are getting sales. Ask amazon for it and they will do it.
4)Mentorship is for 1 year so in case of any problem let us know and we will get back to you asap. Still, you are going good, if there is any mistake we will tell you about it.