Inserting chunks of code into a template on a per-page basis

I’m trying to figure out how best to structure this from a developer standpoint. Here is the scenerio:

I have several pages of case studies, which all use the same template/blueprint. Inbetween certain paragraphs within specific pages, I want to insert custom blocks of code.

For example, one case study might be like this

[Paragraph 1]
[Timeline - custom code]
[Paragraph 2]
[Paragraph 3]

While another is like this:

[Paragraph 1]
[Paragraph 2]
[Image with annotations - custom code]
[Paragraph 3]

What is the cleanest way to accomplish this so that I don’t have to end up duplicating lots of code in different places? Ideally I would like to be able to specify something like [[Timeline]] in the textarea in the panel and it would insert the timeline there.

Here are some options:

  1. Use a custom Kirbytag http://getkirby.com/docs/advanced/kirbytext
  2. Insert a snippet via a custom Kirbytag Embedding Snippets
  3. Use the page builder plugin Plugin for an extended structure field with more then one kind of field set

This is exactly what I was searching for, thank you.