Drupal 8 One-off Custom Page for Theme I'd like to create a one-off custom page which will contain several text fields.

The layout for the page will be custom, placing the text fields in various locations next to design elements, diagrams and maps. I'd like the site editors to be able to update the text fields/labels, including language versions.

I'm generally familiar with the render API, page and node templates, and I do know that I could create a dedicated content type (node, content entity) with all the fields required and then a page template (Drupal 8 custom page template) to render the node (and its language versions). 

Just wondering if it makes sense to create a complete content type for what will effectively be a one-off (albeit important) node/page.

Thoughts? Suggestions?
You might want to have a look at the Paragraphs project. It basically allows you to create different building blocks (Image with text, Diagram with description, ...) and then you can piece them together in the edit form pretty easily.

Check out the demo module that's part of the project for a quick start. You'll still have to actually implement the design for each building block but once you have that, you can easily change how you've combined them and move parts around, add new ones.. create multiple pages that each uses those building blocks differently.