aHA! Ok I did some experimenting, replaced the OnAdd/Del commands with !Alerts instead of my script bangs, and the result was the alerts came up while the tray was loading, allowing me to see what's happening:

Systray2-2.0.1 *does* in fact work, but the problem is this: the systray is fully loading before litestep moves on to loading the next module. As a result, by the time LsBox is loaded and the systray is hooked into its box, all the OnAdd/Del commands have gone through.

Basically the systray is being created, loading all its icons, each of which is calling the bang command to resize and move the tray's lsbox, but the box hasn't been created yet so the bangs just float off into space and have their destiny go unfulfilled. Sad story, really..

So, what I'm looking for now, I suppose, is a way to load systray2-2.0.1 and have it wait until lsBox loads before populating itself with icons. (systray2 has to be loaded before lsbox or the hook won't work)

I've seen some modules that have a command like
ModuleNameWaitForBoxHook
but as far as the docs lead me to believe, there's no support for that with systray2-2.0.1