You can change the default icon (/images/icon.png) with yours. Transparent .png is recommended, 16x16px size.

You can change the default logo (/images/logo.png) with yours. Transparent .png is recommended, 155x155px size.

License your content! But don’t restrict too much. Go to Creative Commons and pick a license. Then open footer.php (or sidebar.php or wherever you want) and mention it there.