Looking at the code you posted, I am 99% positive that you only need to create and add header-buddypress.php and sidebar-buddypress.php to your theme folder instead of changing code in 16 files transferred into your reaction theme in server. Let’s give it a try.
Create the header-buddypress.php file. Copy content of your reaction theme’s header.php and post it in header-buddypress.php and add the following at the bottom of that file:
<div class="super-container main-content-area" id="section-content">
<div class="container">
<div class="eleven columns content">
(updated)
Save file.
Create a new file sidebar-buddypress.php. and paste the following:
</div>
<div class="five columns sidebar">
<?php dynamic_sidebar( 'default-widget-area' ); ?>
</div>
<?php if ( bp_is_register_page() ) : ?>
<script type="text/javascript">
jQuery(document).ready( function() {
if ( jQuery('div#blog-details').length && !jQuery('div#blog-details').hasClass('show') )
jQuery('div#blog-details').toggle();
jQuery( 'input#signup_with_blog' ).click( function() {
jQuery('div#blog-details').fadeOut().toggle();
});
});
</script>
<?php endif; ?>
</div>
</div>
Save file.
Upload both files to your theme folder in wp-content/themes/reaction/
Finally, you might want to modify the default template pack styles, check out http://codex.buddypress.org/theme-development/theme-dev-bp-template-pack-walkthrough-twenty-ten-bp-1-5/3/
