Any way to auto-update auto-bound dropdown on page load?

It looks close : ) The “bubble-element” can be removed if you want, but it makes it more robust. Try changing it to:

<script type="text/javascript">
if ("dynamic_value_to_run_this" === "yes") {
  var seen = "yes";
  $('.bubble-element .Input[placeholder="read"]').val(seen).change();
}
</script>

Only one dynamic value needed.