Hi. Sorry to jump in, but on the issue of displaying in Preview…just getting started with YAML, but mine shows in Preview? Is it the theme that does that?
Just an extra information. If your target is using something like Dataview or similar, yaml metadata work fine. But attention, I think that tags and links inside yaml not working as implicit data, i.e, tags and links added via yaml are not reflected in tag-pane, backlinks and outlinks.