Hi Andrew
Glad you got the marriage information you wanted

I don't know if this is of any help but if you go to the
Lennon Wylie website you will get the Belfast Street Directories for various years. I believe Louisa street was in North Belfast near Oldpark Road whilst Copeland Street was in South Belfast. I don't know if the streets are still there.
If it's a general enquiry PRONI is very prompt but if specific it may take longer. If you haven't had a response after a week or two, drop another wee email and refer to the first - you may not get the info you want on line but you might get something, esp if you don't live locally and cannot visit the premises.