Moving boot partition

Once it is automatically mounted in fstab, you will be able to also automatically mount bind it in a statement further down the fstab file. I do not know how that will work out with the encryption, though. If it is decrypted during mount, then it will work.

A normal line in fstab similar to this should work
/mnt/Backup /path/to/mount none bind 1 1

where the first is the path to the directory on the ntfs file system being mounted and the second is the new mount point. you might consider adding the nofail option to the options as bind,nofail so if it does not work the first time then the system will not hang.

Mount bind doesn’t solve the Dropbox requires an ext4 partition issue.

It should as long as the file system being mounted is already an ext4 file system. That fstab line tells mount to use the original file system type and not explicitly force it to the named type. The bind option handles that feature.

I don’t use dropbox so cannot give first hand experience on that.

I stopped using the official Dropbox app and am using Maestral. So far so good.