EBD doesn’t know about html_id or html_class and EBD doesn’t pass shortcode parameters that it doesn’t know about thru to Contact Form 7. So, those won’t work.
I’m not sure what you’re trying to do exactly, but here are some options:
You could directly edit the email-before-download php file and hardcode html_id and html_class in there where it calls the CF7 shortcode (or maybe you could pay the author – M&S Consulting – something to add that feature and spin another version of EBD.
If you’re just trying to style the form tag and you only have 1 CF7 form on the page then you can use the .wpcf7 class which will be a class on the form tag (much like html_class would do).
If you have multiple CF7 forms on the page or whatever then you can use CSS selectors to get at the CF7 form or div tags by starting from an outer or higher tag and selecting down into them. Or, use javascript to do stuff .. perhaps iterate through all form tags on the page with .wpfc7 class and then style them in some way.
