[reggoboy]

You can also select multiple annotations using then layers window.

Oh, that's a cool trick. Yes, to be clear, what I couldn't figure out was how to even copy multiple annotations. I guess it makes sense that the familiar macOS features of Shift-click and Cmd-click don't work for an iPad-based app. But now I found:

1) press-and-hold on the arrow which selects everything
2) dragging a selection rectangle to select multiple
3) your cool layers approach

Thanks!!