The master filter is loaded in the OnOpenMacro map note in each individual map. (The SYMICONFLOAD command)

Sounds like an interesting, but also very difficult project. A CC3+ map is just a few bits of text really (stored in a binary format) that describes the layout of the entities in the map, so that means that unity would basically need to implement the full render from CC3+ to be able to turn that information into a visual representation of the map.

Lee started talking about the .fcw file format here. Unfortunately, he never finished the job:

While CC3+ itself allows for almost infinite scaling, the symbols and fills themselves are still ordinary raster images (To get the most out of the infinite scaling, you would need to use vector artwork instead of raster, but generally that's not as pretty, and while they scales indefinitely so you avoid pixelation, they aren't detailed enough to really look good when enlarged too much). The raster images provided in much higher quality than you would ever normally need, thus allowing you to export the map at quite a high resolution, but there are limits. Try opening up one of the .png images (you'll want top open up the _VH version of the file) from CC3+'s symbol folder in your favorite image editor, and zoom into it, and you'll notice that you can make it quite big before pixelation becomes an issue.

No. The pixelation is a limit of the resolution of the artwork, so the only thing that really affects that is how large (physical size) you make the final output, there are no way to cheat in CC3+ to affect this, it can't make the images better than they are.

You seem to have made a mistake when you drew your lines. If you followed Sue's tutorial, all your lines should end in that point in the middle of the circle, but it looks like you have drawn them so each line goes through the center and out the other side.

So, when trimming them, you are not just removing the part inside the circle, but the part that sticks out the other side. So when you get halfway round the circle, you don't have any more lines to trim (there is just a white remainder there that will go away on the next screen refresh).

You need to ensure that your lines end in the middle. You can do that with the :CC2SPLIT: command, but it is probably easier to just redrawing them, after all with the circular array, that's just a few seconds.

When you place your tabs, try switching off snap (bottom right corner) before placing them, it might be snapping that interferes with the placement when placing along a diagonal.

The fold/cut lines commands should leave behind a visible line. Just for troubleshooting purposes, try drawing a longer line with these commands on a clear background. That should make them more visible, and a longer line lets you see if there are any issues with the line dashing that makes it invisible.