I've two questions/bits of feedback.
I've created a sign-up form and embedded it my site, but I can't find the options (if they're there) to edit the "Thank You" message in the actual sign-up form, or to add a redirect link to the button.
I also have the Constant Contact plugin on my Wordpress site which does offer this level of customization, but the form itself looks horrendous compared to the native Constant Contact form - at least without excessive CSS editing.
Am I missing something?
There are several types of lading pages that you can create in Constant Contact.
The type you are describing is a Lead Generating Landing Page. This link has the direction on how to make a Lead Generating Landing Page, including how to edit the thank you message and add the redirect link.
I've used that function already but the there isn't enough space for the text that I have on my landing page, which is why I opted for embedding the form instead.
We completely understand how a thank you message for an embedded form would be important to edit. Unfortunately, at the moment we do not have the ability to do that. I will track your feedback on this as well as your feedback on adding more text to a landing page sign up form. Thank you!