See this thread and the Wiki FAQ section, plus you can see current posts but I recommend that you read this which will answer your questions but basically yes, call up before time and unfortunately as I understand it you cannot change names of your travel companion without cancelling the booking and trying to re-book.

Of course there are no gaurantees if you later went down this road then the original seats would be put back into redemption availability.

https://www.flyertalk.com/forum/brit...ad-2025-a.html

As for your Gold question perhaps someone can answer that.