The best way to see what you need for a Master Class plugin in lscript is to find the lseditor.exe and choose a new master plugin template. The structure is quite different from the generic plugins 90% of lscript users write. It's also heck to debug as well.
I believe there are flags that can be set so that it will automatically reload with the scene, instead of you having to re-add it to the scene.
The only master type plugin I've written is in Python, and it was some special kind of heck to get working right.