Remove symbolic link

This isn't du resolving the symbolic links; it's your shell.

* is a shell glob; it is expanded by the shell before running any command. Thus in effect, the command you're running is:

du -s /data/ghs/14 /data/ghsb/14 /data/hope/14 /data/rssf/14 /data/roper/14

If your shell is bash, you don't have a way to tell it not to expand symlinks. However you can use find (GNU version) instead:

find /data -mindepth 2 -maxdepth 2 -type d -name 14 -exec du -s {} +

As alice has write permission to stuff/ directory, alice can modify its contents even if she isn't the owner of the files.

When using Linux ACLs, when file is created (or copied, as copy creates new file at target) permissions are applied as described by man acl. Moving a file with mv preserves permissions when the file can be moved without copying. Looks like for some reason mv can not move the file and does a copy instead, since ACLs are applied to myfile.

Creating a hard link is quite different. Creating a hard link creates a directory entry (at the target directory), which points to the same inode as the original file, in other words, the same file exists in more than one directory. File permissions, both ACLs and traditional UNIX permissions, are stored in the inode. As both /home/stuff/myfile and /home/bob/myfile point to the same inode, any change in either will reflect to the other. This is why alice can access the hard link. The permissions of /home/bob/myfile (777) are the same as the permissions of /home/stuff/myfile.

Symbolic links instead points to the target path. Accessing the file that the symbolic link is pointing to requires the same permissions as accessing the target file. Possibly alice doesn't have search (execute bit) access to bob's home directory, and therefore access fails.