Hi Tony,
Let me answer your questions.
1. When the user submits, the submission will be pending but the user will get notified of the submission via email.
Yes, it is possible. You can follow this documentation to know how to do with coding
https://docs.metabox.io/extensions/mb-frontend-submission/#form-actions
2. and also when the post gets approved
You can also create a custom function to send an email to the user after you approve the post.
3. All the user to edit their post without the user profile/dashboard.
No, if they do not edit the post on the frontend dashboard, they can edit their posts on the backend (admin area).
4. Have a multi-step form
The frontend submit does not support showing multi-step form.
5. Style it better - Remove or don't need unnecessary fields.
You can customize the form on your own with custom CSS code. Create a new field group with necessary fields and put the field group ID to the frontend submission shortcode to show on the form.