Re: karrain, keejiye, karriye...
Realistically, "karein" is an informal, and respectful term, that is used most commonly.
"Kijiye" is very formal. Doesnt even sound 'normal' in routine conversations.
"Kariye" is also somewhat formal and abnormal.
The above is with respect to normal conversational urdu in Pakistan, in general. There are families in Karachi with Indian backgrounds that use "kijiye" and "kariye" routinely, but trust me, it sounds very formal. "Karein" is the way to go, if youre a mainstream Pakistani.