Not sure I’m grasping the difference between the two but the idea behind paraphrasing is pretty straightforward, it’s the practice that’s hard as there are so many variables with text and text patterns. Good paraphrasing is often about having good grammar, not the essentials of what paraphrasing is; unless good grammar counts as essential processing. So I’d say Harvard Referencing has the most essential processing.
Summarising seems a good example of generative processing. If we take the example of introductions, is identifying different parts of an introduction previously introduced generative, or is it not until the student writes their own introduction that it becomes generative?