As long as you have your information from you nwncdkey.ini, it doesn't matter what set you use, yours or someone elses. All your key codes are in that one file, even the expansions. So just find and save that file, install and use what ever keys your friends have and then replace the file created with your own.
After that, make a copy of the entire install as it doesn't require any registry keys to play. Just put the folder on your drive and launch the nwn.exe or the nwnmain.exe and you will be good to go.