Redmi 6A has 2.0 GHz MediaTek Helio A22 quad-core processor.
No. Redmi 6A does not have the removable battery. It has a nonremovable battery.
No. Redmi 6A does not have the NFC support.
No. Redmi 6A does not have IR remote sensor. You cannot control your TV or AC with it.
The Redmi 6A is a fairly good update to the Redmi 5A, which itself was barely any different compared to the Redmi 4A. You now get a tall screen, better processor, and improved polish overall.