I'd keep the Pre Stream Program as a separate program, with a custom program channel which has the following statuses, in addition to more as needed.
1. Track 1 2. Track 2 3. Track 3 4. Track 4
The operational smart campaigns can stamp the status as and when relevant, and if a higher status is achieved, the lead won't move back to a previous status. Based on listening the status change, you can push it to nurture and specific stream. Because these are program statuses, a lead won't have more than one at a time and you can define the priority as well. The caveat of false positives is pretty real, as Michael points out, you may want to filter the Bot Activity to address the same.
The operational campaigns could mean a specific smart campaign (for every unique URL) to count the number of unique clicks on a CTA (may need the UTMs if you have multiple links in the same email and want to count them differently). To count update program member custom field (this is a useful field to manage counting program specific counts of links in other programs as well)
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