Add network share to favorites via command line?

The command below should mount the network share, the reason its not very well used is you need to pass credentials in the in the command which is very insecure. 

You can also use the following command: open “smb://name@server/“  Replace “name” with your username and “server” with the server’s fully qualified domain name (FQDN). If required, the command will prompt you for your password. This command can be used to mount a shared drive. 

I would recommend taking a look at Network Share Mounter. 

Closer to the original request, you can try your luck with sfltool or mysides, but methods vary from one OS version to the next, and there may not be any working ones at this point.