I've got the calendar of my favorite soccerteam in my gmail, that worked without even adding it on my Redmi 2.
I have shared my calendar with my wife , so we can both see which appointments we have. But you want it the other way around, that is difficult for me to test
In that case, I still think it is a setting on your phone.
Did it work before you switched to Miui or this phone?
Have you checked all the displayed calenders?
I see:
Birthday reminders -unchecked
Local calendar - checked
PSV Calendar - checked
Weeknumbers - checked
My own Google account - checked
Holidays in The Netherlands - checked
Birthdays of contacts - unchecked
Other Google account - unchecked
As test for the Hotmail account, it is all unchecked, because I don't need it anymore:
Holidays
Birthdays
Hotmail account calendar