this is for ODIs (not T20Is):
Think Thakur is in the top tier of seamers (above Natarajan), as he is fairly smart bowler with variations but he can also contribute a quick 20-30 runs with the bat.
For spinners, I dont know of India has a spinner that can play purely on bowling ability. Chahal comes the closest, but attacking sides will beat on him. Good thing is he doesnt go too negative/depressed like Kuldeep when taken to the cleaners.
I think India needs to continue developing spin bowlers that are all rounders. Jadeja is an obvious when healthy. One of Sundar or Axar (preferred slightly as he is a better bowler) should be given a chance as they can both bat.
Here is my first India team for ODIs when all healthy:
4 bats: Rohit, Kohli, Dhawan, and Iyer. Backup: SKY.
Wicketkeeper: Pant. Backup: Rahul.
3 all rounders: Hardik, Jadeja and Shardul. Backups: Axar, Sundar, or Krunal.
3 bowlers: Bumrah, Bhuvi and one of: Shami or Chahal (depending on pitch). Backup: Natarajan, Siraj, Saini, R Chahar.