Thanks Tom, that worked and I could go forward with that.
However, what I was really hoping to do with the wp_show_posts shortcode was use the Lists more like templates. So I could have 2 Lists (with no taxonomy specified in the dashboard) and then use those over and over, wherever I want in various pages, specifying the categories and tags wherever I use them through the settings. So the templates are always the same and the data is different. I don’t think the function you provided above would allow me to do that, since the category and tag are tied to the List ID. Using that, I think I’d need to create dozens of copies of those same Lists and then dozens of copies of that function to match.
Any clever way you know of to accomplish what I want? Maybe something else I can add to that if statement? Basically just some way I can differentiate each instance of the List, so that I can assign a different category/tag combination to each.