On (4.), what is killing your children before their task is done?

There are lots of ways to talk to child processes. If there is a small fixed set of messages, signaling with kill is effective, with %SIG copy-on-write. If you need more extensive communication, pipes are my favorite, but sockets are also good. Each child will need to parse what you send it. See perlipc for details.

Another way is to only launch a child when it and the parent will know what it's supposed to do. That's best on systems, like Linux, where fork is cheap.