I wrote a tool for that: http://cc.monsen.cc/tools/cc3monsentools.html

Yea, that's DELAYDRAWSYM.

That setting is system-specific and not map-specific, so it won't be automatically turned on when people load the map unless is it is added to the map loading macro.

I can't provide a full explanation here, especially since this isn't really something I have really noticed myself.

But let me address one thing at least:

All CC3+ maps have a setting that determine if effects are on or off on load, you'll find this in the :CC2RESMODE: dialog. This is a per map setting. If this is off, the map is loaded with effects off, even if it was turned on inside CC3+ previously. You can override this behavior from Tools -> Options

Now, while you experience that effects randomly turns off, I don't know, but i suspect it could be due to loading a file that sets this value. There are lots of cases where CC3+ loads map files, for example, symbol catalogs are actually just map files with a different extension, and drawing tool previews in the symbol catalog window can also be map files. I am suspecting that maybe the value is incorrectly set when something like this is loaded.

You can just rename it. The maps doesn't refer back to the .fsc file even if you've inserted symbols from it. As long as you don't rename any of the underlying art (png) files, or the folder/path they're in, you're fine.

What Sue says about using the PNG instead of the symbol id right, but you don't need to go around hunting for the png, simply place the symbol you are going to modify, then :CC2EXPLODE: it, that will turn it back into it's individual parts, for most png symbols that will be the image it is made from and nothing more.

But, you also said something about sheets. Do note that symbols DO NOT contain any sheets. When you define a symbol, sheet information is lost. So when creating a symbol, you should always place everything on the same sheet and just rearrange things with the front/back buttons. This ensures that ordering is proper.

(A symbol CAN go to different sheets if you use the line style to sheet options, but this splits it into several symbols on placement.)