I think you have to add the following to smb.conf:
follow symlinks = yes
wide links = yes
unix extensions = no
Unfortunately, it appears that OSMC (like Rasbmc) doesn’t actually use /etc/samba/smb.conf, but rather uses it another copy (which I can’t find.)
As a mater of fact Samba on OSMC does use /etc/samba/smb.conf.
I think you actually misunderstand what the follow symlinks option does, and the fact that it is a setting to configure the samba server, not the samba client in Kodi.
When a client tries to open a symbolic link on a Samba server share, Samba attempts to follow the link to find the real file and let the client open it, as if the user were on a Unix machine. If you don't want to allow this, set the follow symlinks option like this:
follow symlinks = no
So it controls whether a client connecting to the samba share on OSMC can access files/folders that are actually symlinks on OSMC.
It has nothing to do with following “windows symbolic links”. (I assume you mean reparse points)