In case this helps anyone else, I finally achieved what i outlined above using the code below. The stage holds a symbol called allButtons, which holds two symbols, Button1 and Button2. The symbol elements of these are the click targets, and have the class btnClicka.
$(".btnClicka").on("click", function(e){
var targetID = e.currentTarget.id;
var buttonClicked = targetID.charAt(targetID.length-1);
console.log("click " + buttonClicked);
sym.getComposition().getStage().getSymbol("allButtons").getSymbol("Button" +buttonClicked).stop("Touch");
});
To me, this does not seem like an elegant solution; is it necessary to go all the way out to the stage and back in again to target what I want, when it's only one step away from where I started. Seems like walking round the block to visit the house next door. If anyone knows the shorter/ clever way to do this, I would love to know.