First, great fix and this seems to work for me too.

I think the Parts_ListOfComments needs to be addressed as well in here because if you only do Parts_CommentForm, you can still get a list of comments or, in my case where I don't import the comments to Orchard, I get for every blog post "No Comments" immediately before the Disqus wrapper. Right now I'm handling it by universally hiding that part within my placement.info file as I'm not sure how you can override this to not place anything.