I have downloaded the same template so I can see the files you are working with now.
1. To amend the comments box on your homepage, you need to replace the code I suggested before:
<?php comment_form(); ?>
With the following:
<?php include('comments_home.php'); ?>
Then create a new file in your template directory called 'comments_home.php'. Open it and paste in the following:
[Code moderated as per the Forum Rules. The maximum number of lines of code that you can post in these forums is ten lines. Please use the pastebin]
The submit button should be on show because otherwise users cannot easily submit their comment - it also helps for accessibility.
2. To remove the RSS subscribe links, open your sidebar.php file and remove all of the following:
<h3 style="font-size: 150%;font-weight:100;"><img alt="RSS" src="<?php bloginfo('template_directory'); ?>/images/feed-icon-16x16.gif" /> Subscribe</h3>
<p><a href="<?php bloginfo_rss('rss2_url') ?>">Entries RSS</a> | <a href="<?php bloginfo_rss('comments_rss2_url') ?>">Comments RSS</a></p>
Sorry for the long response. I hope that makes sense. If not, please respond.