For measuring all-round performance over the year, I normally consider 20 innings batted and 2000 balls bowled. No one qualifies for these. An alternative set of criteria include 10 innings/1000 balls/1 fifty+/1 4+wi.
Then we get:

Stokes has the best performance, followed by Ashwin and Jansen. His batting average is considerably better than that of the others, while his bowling is not so good. Still, we find that his overall all-round performance is the best.
Finally, we look at all-round match performances: 50+ and 5+wi in a match

/Here we see that Jadeja’s century and 5+wi are the best performances here. Next would be SA’s unsung KA Maharaj, who also crossed 1000 runs/100 wickets in this period.
Now we have compiled the best individual performances for the year. It remains to see the best performances by Test debutants and captains.