Can we output individual form items within a Layout?
That is not how you're supposed to use layout templates as those should be for for placing content, just like normal Drupal regions, and then modify the output using field and node templates. The general idea being to be able to reuse the templates in other places and as such reducing the number of templates needed.

Of course you can output content directly in the layout template. I would recommend you install the Twig Tweak module. You can then use {{ dd() }} to see what is available to you. As an example you can display a field value like this:

{{ node.field_myfield.value }}


It depends on what you want to display, but that's the general idea, very similar to the node template.