Well for you as a sponsor, I DO NOT believe have to submit anything in original (Photocopies showing your identity is fine).
I have filed for my spouse from Pakistan. The only original I have provided is "Birth Certificates from NADRA" and the rest all photocopies. I would suggest everyone to NEVER submit anything else in original. To show legitimacy , I have seen some if not a lot of people submit their sponsoring spouse's educational credentials in original. Please never do that. Cause if they do not return (Which may happen) it can put you in a situation or if you need your docs for any other purpose and have to request them back, you may get your file delayed un-necessary.
The best practice (In my opinion) is to provide them with attested photocopies from an authorized notary. In your case you will need to submit the following two in original (Recommended):
1- FRC "Family Registration Certificate" . This proves you both are married, as it shows yourself and your spouse at one place and is considered to be a government issued doc.
2- Birth certificate of your spouse (NADRA).
3- Now a days, NADRA also issues your marriage certificate. So it is again advisable to get one and PROVIDE CIC WITH AN NOTARIZED COPY UNLESS ASKED FOR ORIGINAL.
Its better to post your questions to the threads (Pakistan applicants) where people have great experience to advantage from.
I hope this helps, good luck and if you have any questions, feel free to send me a private message. Cause with so many threads, I have a tendency to forget to the threads I have answered :-[.