Re: prename - old-fashioned?
I have never seen or used prename or forename, though I see the latter has 76 million hits. Perhaps that one is used more often in the UK. The most common way, as the Goggle results show, is "first name" but as we become more global and realize some cultures have their family name first and the name their parents pick out for them second, "given name" is becoming more popular. I recommend with an American audience you use "given name."
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.