If you are sticking with threads, you can pass objects to threads using the Thread::Queue module. In fact that is also the recommended (big Camel book) way to synchronise the handling of asynchronous requests under those circumstances, although if you use it to meet both requirements you'd need N+1 queues where N is the number of startup threads - one to synchronise requests to the request-handling synchronous daemon and one for each startup daemonet to receive object data from the initialising parent.

And if the threads approach remains too troublesome, you could always spawn the daemonets with something like for (1..$nrDmnts) { my $pid = open my $ph, "|-" ... } instead and send them non-shared data across the pipe.