Lack of tag is just an oversight. I've added a 'Character' tag now. You can edit your post to add it if you wish.

As for music instruments, I don't think there is any available except for the harp. Maybe one of the free community symbol sets have symbols seen from the correct angle that it might be used. I don't think there are any Character Artist compatible symbols, but a top-down dungeon-scale symbol might work. Likewise, you may find an image on the internet which is usable.

When you add new fill styles, drawing tools won't be created automatically for them. This is partly because drawing tools are specialized tools for different purposes, not a one tool per fill type of deal, as you can see some tools are smooth polys, others are fractal polys, they have different kind of outlines based on their purpose, they are set to go on the appropriate sheet and so on.

When you import fill styles you can manually create your own drawing tools that include these, but more commonly they are accessed by clicking on the Fill Style indicator in the top right of the main CC3+ window, and go to the bitmap files tab. Here you can see all the fills in the map (with preview), and whatever you pick will be the current fill which will be used when you draw things with the basic tools found in the right hand toolbar. Of course, when you use the basic tools, you also have to remember to set the sheet and other properties manually too.

Looking great.

And I love the endpoint modifer too. One of my heavily used tools.

Unfortunately, the symbols in area don't obey the random rotation symbol properties.

As for steampunk, nothing in the official symbols as far as I can remember. Would have made a nice annual though.

The Hatch style is set in the Outline options for the tool.