Other members asked about an rss button i think, IIRC Daniel said it’s planned.
Instagram I dunno. Just ask him ?
Or You can customize you pinboard theme.
In theme option page, use Dribble account line (in this example) to add your personnal Instagram link. Then replace the icon that you can find in the installation folder of Pinboard theme :
with your custom Instagram you have to make, with the same name (flickr.png), in the same size and layout as the flickr.png file.
This is the easyer way to customize… or wait for an update !!!
Another way is to modify function.php, style.css and includes/theme-options.php (if I don’t forget anything!) to add an one more button for Instagram, not so big deal but this need more skills…