I was able to get collapse working with the following tweaks:
In collapse.vue change:
hub.$on('toggled::collapse', function (data) {
to:
hub.$on('toggled::collapse', (data) => {

That way this.id returns the expected value.

Also in collapse-toggle.vue there are two calls to emit the "toggled::collapse" events. I had to remove one of the calls.

Similar changes will be needed to the analogous accordion code that seems to be stubbed in.