If it is the last diagram, you can use switches that have a radio in the add-on.
For example, here is an Add-on switch.
This switch does not control the load but instead “pretends” it is on/off (or dim if needed). You can directly associate it with a master switch or use smart lighting rules in SmartThings to pair it with any master switch you choose. With a V2 hub and smart lighting, most setups can be configured to run locally (works even if your internet is down).
Important caveot, if you want direct association (works whether or not the SmartThings Hub is on), you’ll need a master switch that supports association. Also, you’ll have to use something like a minimote to pair them since the SmartThings Hub doesn’t support configuring switch-switch association.
Linear master switch with association: