First, to clarify, I meant we might have existing systems in Scrivener to help you out. There isn’t much I would recommend using Explorer for—save for the organisation of whole projects.
Thanks for the example. Custom meta-data would help you out for this specific usage, definitely.
Some ideas for you, perhaps some will help, or at least give you an idea that can let you shirk the whole spreadsheet system:
- Keywords could potentially be used here—depending on how specific you get in the descriptions, or if you rely on certain patterns. To be clear, I don’t think it would be practical to try and encapsulate all of the data in your example using keywords, the question is whether slightly less data would be just as useful to you. Is for example, the keyword “Discovery” using the “Mystery” plot-line colour a sufficient indicator for the “finding a clue”? Is perhaps having “Lia” as a keyword using the Major-Character colour worthwhile to have attached to the scene?
- Is this a typical scene, this level of activity, or are most of them simpler to describe? If this is an outlier, perhaps just using the Synopsis field to fill in the blanks is a better approach, it being such an action-packed scene.
- Can the scene itself be represented in more atomic terms in Scrivener? By that I mean, does it need to be one single file? With this much going on, maybe it should actually be three files indented beneath the “scene” file itself, turning these descriptive traits into individual synopses or titles rather than what is essentially (at least in my interpretation of the data) a compound synopsis. How entwined they are no doubt makes a difference, though I have no hesitation toward even a paragraph-long section.
Here is a screenshot of how I personally approach this very sort of problem (and I even have access to custom meta-data), using your example data:
In the Binder you can see I have a scene selected, “tons of stuff happens” (though I’m sure the actual name would be more useful 
). I can at a glance see that this scene involves these three plot points, what specific details within that plot they pertain to, and hit Ctrl-1 to start working on the scene text.
Anyway, a few ideas to work with there. Hopefully you find something useful!