For the first issue, I would use GP Hooks to insert your widget into the After Header Content hook. You can use a plugin like this to turn a widget into a shortcode, which you can add into GP Hooks: https://en-ca.wordpress.org/plugins/widget-shortcode/
As for your footer, you can add a border to your paragraphs like this:
.footer-widgets p {
border-bottom: 1px solid #000;
padding-bottom: 15px;
}
I should mention that you’re still totally free to build your footer in Elementor – you can insert it into GP using our Hooks add-on.
Let me know if you need more info – we’re always happy to help.