Marc,
1) You can try to use some div with unique class or ID to styling customization, but we want to pay your attention on that fact than some form styles are dynamic and less-based (defined via style tab in the admin panel). To overwritten these styles you need to use form ID, as sample, if you need to change button hover color you need to use following code:
#[form_id] .scfp-form-action .scfp-form-submit:hover {
background-color: #[some_color] !important;
color: #[some_color] !important;
opacity: 1;
}
where, [form_id] – ID from form shortcode.
If you use widget, you can find [form_id] via FireBug (or other dev tools) or by viewing of html-source of the page.
2) By default, WordPress doens’t use SMTP for notifications.
You can use some third-party plugin for this purposes.
More information you can find on our demo site in the FAQ section – https://wpdemo.webcodin.com/wordpress-plugin-wcp-contact-form/documentation/faq/ – “Why I don’t receive email notifications?” topic.
And yes, after the form submission you will have a record in the Inbox and 2 notifications (admin/user) – based on the settings from Contact Form > Settings > Notifications tab.
We hope, that this information will be helpful.