You can fix the HTTPS problem by using HTTPS locally with a self signed SSL certificate. Heroku has a great how-to article about generating one.
After setting up SSL on all of your development servers, you will still get an error loading the resource in Safari since an untrusted certificate is being used(self signed SSL certificates are not trusted by browsers by default because they cannot be verified with a trusted authority). To fix this, you can load the problematic URL in a new tab in Safari and the browser will prompt you to allow access. If you click "Show Certificate" in the prompt, there will be a checkbox in the certificate details view to "Always allow content from localhost". Checking this before allowing access will store the setting in Safari for the future. After allowing access just reload the page originally exhibiting a problem and you should be good to go.
This is a valid use case as a developer but please make sure you fully understand the security implications and risks you are adding to your system by making this change!