What is required to receive output events from a plugin?

thank you for the advice;
my audio client simply runs on the same thread as the UI of the plugin; (each plugin has its own thread and so also its own audio client) ; the host is not using any external ports; it simply processes the inputs and outputs virtually within my host DLL/EXE module, without any ASIO or other access. The main UI of my app runs either in a different EXE process or at least in a different thread (if the host is loaded as DLL). Since I yet use the default implementation for parameter changes, I cannot use multi-threading yet, cause as you pointed out in this post that implementation is not thread-safe itself.