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.
No. You can not record slow-motion video with Redmi Y2.
Yes, Redmi Y2 does have the OTG support.
Yes, Redmi Y2 does have the bokeh mode.
Yes, Redmi Y2 does have the EIS for the video recording.
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.