I haven't used the Galaxy for sending emails, so was curious about your post. Here's what I found.
If I go straight to Gmail via the Galaxy home screen, I get the screen shown on the top half of the below photo. I can't find a way of locating the contacts, but if I write an email, I get the contacts prompted as I type, so they're there somewhere. As for Google Drive - no idea.
However, I have the Galaxy protected by Norton 360 multi device and when I load Gmail via the Norton Password Manager, I get the screen shown in the bottom half of the photo. As before, I can't see the contacts list but do get prompts when I type an address. Google Drive is one of the sub-menu items under the "More" tab.