No. None of the Xiaomi phones comes with the earphone. You have to purchase it separately.
Yes, Redmi Y2 does have the portrait mode for the rear camera. The front camera does not have the portrait mode.
No. Redmi Y2 is made of industrial grade polycarbonate material.
Yes, Redmi Y2 does have the IR blaster.
The Xiaomi Redmi Y2 is a slightly better attempt at a selfie-focused smartphone than the model it replaces. It has proven hardware that is capable of delivering a smooth user experience, plus MIUI 9.5 which has a lot of added features.