That probably doesn't answer your problem, but for the record, there is something that looks like symlinks (january 2019), but is not.
In particular you can't change the target without recreating the link, which changes its URL.
You can create such links from the GDrive web interface by selecting a file and pressing Shift-Z. No idea why they made it so invisible. It works with files and dirs, but don't behave exactly as you would expect from symlinks. Think of them more as "same file in two different locations".
- Names of all files (the link and the target) are sync'ed. You rename one, they both change names
- I haven't found how to change a link target (so probably not useful to the OP)
- If you "remove" one (web interface, right click > remove), one is moved to trash and the other disappears
- If you sync files to a computer (with google B&S), they appear as distinct files on your filesystem, then B&S syncs them. If you delete one, B&S deletes the others
The only (very lightweight) documentation I found is here. The rest comes from my (short) personal experiments.