do_action( 'comment_form_before' ); is called on line 1553 of /wp-includes/comment-template.php, right before the output of the comment form, that should handle that one for you. I’ll update this if I can find the hook before the comments.

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It seems like you might be able to modify Walker_Comment (found in the same file as above) to output the first link with __construct or something, but I can’t give you precise implementation at the moment (for lack of time).