Having said that, if I have to entertain this idea then I'd focus on finding a replacement for Ashwin and Jadeja, the former in particular. Ashwin singlehandedly won us countless series at home with the ball and sometimes bat.
I doubt we will have a perfect replacement, especially for Ashwin because I don't really remember anyone bowling off spin these days the close to someone will be Washington Sundar but he is untested and definitely need lot of experience to have the tricky mind of Aswin like player who often do unorthodox techniques in his bowling.
We have hand-to-hand replacement for Jadeja which is Axar, but I don't think Jaddu will be leaving the long format at least for the next 3 years.
True, it's impossible to replace him as a cricketer and not many in the domestic knocking on the door with their off spin. There are fair amount of Leggie and left arm spinners tho and some of them are really good, with age in their favor but it feels like a drought of fresh blood in the off spin department and oldies like Jalal Saxena, K Gowtham etc still leading the chart in the domestic.
Washington is an interesting case, he isn't even a first choice spinner in his domestic team and only got in the test team when he was part of the India tour of Australia, he was a bowling reserve for practice only and never meant to debut there. His batting is a big plus but it won't matter as long as you are not improving with the ball and so far, he didn't show any positive sign.
I guess, they will have to replace Ashwin with 1 batting-spin and 1 spin batting allrounder and hope they chip in together and bring at least 7-8 wickets and contribute with the bat.