There's a quick and easy solution to this problem (if you understand PHP).
Step 1:
Add the following lines to your theme's header.php file immediately below the call to wp_head():
<?php if(is_front_page()) do_action('jdm_head'); ?>
Step 2:
Open the main file for the Featured Content Gallery (content-gallery.php) and edit the following lines at the end of the file:
/* we want to add the above xhtml to the header of our pages: */
add_action('wp_head', 'gallery_styles');
add_action('admin_menu', 'gallery_options_page');
Chance them to:
/* we want to add the above xhtml to the header of our pages: */
add_action('jdm_head', 'gallery_styles');
add_action('admin_menu', 'gallery_options_page');
Assuming the featured content gallery is on the front page of your blog (like it is on mine) this completely solves the conflict problems between the two plug-ins.
You can check out the interaction live on my site. The home page is http://www.jumping-duck.com and the e-commerce store is http://www.jumping-duck.com/store.
Good luck!