No. These elements don't have a color, they are drawn on the screen using an XOR function, which means their color is always the opposite of what is below them. You can see this in effect yourself by drawing a solid black square and a solid white square next to each other, and see how the grid dots and crosshairs actually have different colors depending on where they are.

This is intended to make them visible no matter the background color, but for busy fills it may still be difficult to see them. For the snap grid dots, you can also experiment with a different size/design of the dots.

You can run the LISTIMAGENAMESDWG command to do this. It will list all the images in a drawing, and tell you if it is a fill style image (bmpsty) or a symbol/inserted image (pictr2)

You can also use my custom command that list images sorted by addon. Note that the accompanying data file is a bit out of date, so a lot of files will be identified as unknown add-on.

Have you configured the glow/shadow effect to be in percent of view width perhaps? That really messes things up when you view from different zooms, or make different sizes exports.

That's great to hear. I think that is one of the main parts of a competition like this. Experminent, learn and have fun. They give you an opportunity to make something you wouldn't normally do.

Map looking great so far.

While $50 is dirt cheap for a commission, some people may find it a bit expensive for buying a digital copy of an existing map. I often back various kickstarters, and for that amount, you usually get 20-40 nice maps for that price.