How does one create a template that instead of symlinking to the master site files, symlinks to a slave site?

I want to create multiple sites but do not want the slave sites to have multisites stuff installed into them.

I don't really understand your question.

If you want create a slave site, you need to have access to the Joomla PHP code.
This require to share the Joomla files and folder on the disk.
The requirement can be acheived either in the hosting configuration where you give the same path that you master website or using the Symbolic Link when it is available.

On the slave site, the JMS component must not be installed.
It is only required on the master website.
I don't see which JMS stuff you mention. Can you be more precised.
JMS allow each website to have its own Joomla configuration.php file that can be in a specific directory when deploy the slave site into a specific directory with the Symbolic Link. The symbolic link are just there to share the same files and folder on the disk and you have a full control on them in the "Website Template". You can decide to ignore some of them if you know exactly what you are doing and that you are a Joomla expert.

I want to symbolic link Slave2 to Slave1.

JMS creates the Symbolic Link (SL) always on the master.

In fact, in you picture you have not mentionned the links between the Slave 1 to the Master.
I don't understand why you want to create a link between slave 2 to slave 1 as the Joomla PHP code is only present on the master.

Create a link between Slave2 to Slave 1 and afer Slave1 to the Master to retreive the original Joomla PHP code does not provide anything more than directly access the master from the slave2.