If I use the WordPress plug in to publish to our WP site, will the Unbounce page display just as it does on Unbounce, or will it inherit our navigation header and footer?
Great question. It will display just as it does on Unbounce. The only thing different will be the URL, which will be an off-shoot of your main WordPress URL.
No navigational elements or scripts or anything from your WordPress theme will be brought into the page.
Nicholas is right but also keep in mind that if you happen to have another WordPress page with the exact same URL, it will get overwritten by Unbounce.