I can find a lot of the optimizations well enough on my own, I’ve just not gotten around to it yet. Thanks though!
For the second, I had been using the yearly notes since they allow me to both put it into a task list (which I can then pull to another file tracking what I still need to do) and give me a machine-readable earliest/latest date, but I suppose with some of the later tweaks I’ve made to the templates/scripts I now have the ability to input the data as *-within-range pairs on the file itself and still have it show up everywhere I need it to. I’ll be doing that move manually, but is there actually a syntax for editing the frontmatter like you suggest? I know it’s possible with Templater, but it’s a bit late for basing an entire solution around that plugin.
Still, that’s an answer about optimal code, rather than about caches/reusing data.