Can anyone interpret verbose shutdown messages?
It depends on each executable.

The closedown process sends a signal SIGTERM to each process and the process should then cleanup and shut itself down. This includes subprocesses and that appears to be most of the lines in your log - perhaps the parent does not shut its subprocesses down when it does, also see Unix zombie processes in wikipaedia

I would suggest that the original parent has not behaved 'properly' but probably does not matter unless there become many more zombie processes when the OS could run out of process handles.