No. these files are essential to open your vault together with your password. the files with *.bkup are backup files that are created just in case the other file gets damaged.
Why are these files in the cloud and why isn’t this a risk? see here: Why is the masterkey stored in the cloud?
As the google sync client does not know anything about the files IN your vault, it will of course just mirror the encrypted vault files.
Yes. But please make an additional backup of your files somewhere else. This is not a solid backup strategy. For example: if you damage/delete a file in your vault local, it will be damaged/deleted on GoogleDrive as well as soon as the sync starts (which is usually immediately). So please do your backups anywhere where you can restore them without relying on Google. I always recommend a 3-2-1 backup strategy