For the wallpaper you could have a custom print run done. I own a small printing company in the UK and we do bespoke wallpapers from time to time. Not sure where you’re based, but I’m sure you could find someone localish to you.
With regards to the design, unless you happen to find an exact match, which I’m doubtful of, you would end up just ‘taking a guess’ to create the rest of it. Or adapt the design into something you like yourself so you have old and new both in one.
It’s marketing. Someone who signs up for the free email might not interested in drive. But then to get extra space in the emails they need to follow the tasks that make them interact with the other products, which will help gain people’s interest.