I am not convinced India should be playing 3 wicketkeepers at a time in the WC. In fact, I would choose between either Karthik or Pant and not both of them together, in my WC squad. I do not care about T20I's but for WC, both cannot go. And it seems like Rishabh might win considering his age, his left handed batting variety and the fact that he can bat at any stage of the innings as opposed to Karthik whose utility is mostly when it comes to batting in the very fag end of the innings. I have a strong feeling Karthik will lose out on his place.
I would not take Umesh Yadav to the WC. I would rather have Khaleel as the backup seamer even if he goes for runs. India is mostly going to be served by Bumrah, Shami and Bhuvi in the WC. Among Khaleel and Umesh, I feel Khaleel is the better of the two options since he has a left handed variety to him and that can be useful at times. Umesh to me, does not inspire confidence that we can take him in the WC.
I would reserve judgement on KL Rahul. His batting technique has changed drastically and that's helping him in home T20's. Just because of this innings, we cannot say that he is good to be selected for the WC squad. To me, the backup opener in the WC squad should be Ambati Rayudu and KL Rahul should play T20's exclusively until he can prove in domestic cricket that he can be inducted back into the ODI or test side.