1.
Shouldn't the PluginWindow class from the Plugin-Host example should be moved into one of the modules, so it can be reused for own hosts, something like a base-class for all Plugin-Windows?
When ever there is fix (last time its was the Scale-Factor problematic, new VST3 isseus) if have reimplemented it in my own host.
2.
Does the current PluginHost/AudioProcessorGraph react on Plugin-Latency changes? - It seems not
It would be better if more of the plugin-handling stuff will be moved into the modules
(or do you want to make it more complicated to support a own plugin-host implementation ;)