You cannot extend a single node cluster.  

Seems to function fine from the current single node 

What Im asking is, Is it possible to add a storage only node to CE? 

You cannot extend a single node cluster.  

Seems to function fine from the current single node 

What Im asking is, Is it possible to add a storage only node to CE? 

You cant expand a single node cluster. That you can see it in the gui doesnt mean you can do it. 

In the CE installer there is no option to install a storage only node. Maybe you can select it if you have a three node CE cluster and expand it with the forth ce node. 

As Jeroen said, a single node cluster cannot be expanded (CE or not).   

Storage only nodes are really just nodes where they have been set to not be schedulable by AHV (or in the case of storage only nodes deployed with ESXi, they’re running AHV so ESXi can’t schedule VMs on them)

My recommendation would be to build a 3 node cluster, with two nodes having enough CPU and memory to run the CVM (and maybe FSVM if you’re working with fiels) and then your MS-01 to run your VMs, then just set an affinity rule that keeps your VMs from running on the other two storage only nodes.

You will need to rebuild your cluster from scratch though.

Why can you not expand it? That makes absolutely no sense. I stood up the cluster originally without selecting 'single node' and the expand options didn't exist anywhere. Seems like a pretty large missed opportunity especially advertising scalability and flexibility