No. Redmi Y2 can support only one sim card on 4G network at a time. Another sim card will be either on 2G or 3G network.
Yes, Redmi Y2 does have the LED notification light.
Yes, Redmi Y2 does have the IR remote option.
No. Redmi Y2 is not a waterproof mobile phone.
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.