While CC3+ can't import data files like CSV or similar,most drawing commands in CC3+ can be executed using a macro command. So if you are capable of writing a translator yourself to turn those CSV data into CC3+ text commands, that command file can be fed into CC3+ to draw things automatically.

More like up early, caught it before going to work :)

For line styles, look at this:

This is true, but remember that if you do it this way, you are giving up a couple of the advantages of symbol catalogs:

• When not importing them, you don't automatically get the 4 resolutions created either. This means CC3+ will use the highest (and only) quality available for your symbols regardless of zoom level. This can impact performance
• You don't get to set useful properties like which sheet they should go on or things like symbol groups or smart symbols.

FT3 have limited support for adding details outside the actual planet. But you can use the Image Overlay. Should be a separate menu for it. From the overlay window, you can create new overlays to use as a drawing surface, and the Overlay Paint tool lets you paint on the overlay.

Not that the size of the overlay is it's resolution, so to avoid having country-sized pixels, you probably need to bump this up a bit from the default selected size of 512x256 when you create a new overlay.

You can export the overlay to an image and work in it in an external editor if you want more advanced painting tools, and then import it back into FT3.

@Wyvern's answer is great, but you can shorten it a bit to make it a bit easier (There is no need to do the combine step). Here's his text with just a few small edits from me