The peer review comment box functionality you want doesn't currently exist, but you can hack it in by editing the file templates/submission/comment/peerReviewComment.tpl. You are looking for the comment boxes (<textarea> tags) with the ids "presenterComments" and "comments", respectively.
You'll notice that the peerReviewcomments.tpl file is written with Smarty template code. You don't necessarily have to understand the Smarty tags: you can just add the text you want to appear in the box between the textarea tags, and it'll appear in the comments boxes in the system. However, if you are planning on using more than one language, or if you want to do this in a way that won't break when you next upgrade, you'll have to do more work. I can give you a few more hints on where to go next if you'd like, but take a look at the file first. Please remember to document any changes you make in case you break something, or for when you next upgrade.
With respect to the emails: you can edit those by loggin in as Conference Manager and clicking the Prepared Emails link in your User Home. When you make changes to those emails the changes will be saved when you upgrade; they will only be reverted if you hit the "reset" button.