You would never expect it, because the mouse pointer changes and the Color Preview swatch does not update, but you can use the color picker outside of the Softimage window. Just activate the color picker, point outside the XSI window, and click.
So, for example, you can open an image in a viewer and grab colors from the image into Softimage.
By combining -script and -render, you can use a script to set up a scene for rendering. xsibatch loads the scene, runs the script, and then does the render.
Any changes made by the script are not saved.
You can also use -script with -export flag. For example, if you wanted to change the output folder for .mi files, you could do this:
xsibatch -processing -export \\server\share\xsiDB\Scenes\test.scn
-script tmpChangeOutputDir.js -frames 1-5 -pass all
where the .js file changes Passes.RenderOptions.OutputDir to the desired output location.