Yes, Redmi Y2 does have the bokeh mode.
Yes, Redmi Y2 does have the support for Miracast.
No. Redmi Y2 is made of industrial grade polycarbonate material.
Yes, Redmi Y2 does have a dedicated MicroSD card slot. You can use 2 sim cards and a memory card at the same time.
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.