Unfortunately product does have such thing yet. but you can use below script to achieve this(function ($, $document) {    // Adding action on layer    $document.on('cq-layer-activated', refreshPage);    function refreshPage(ev) {        try {            // Get edit mode page iframe reference        ...

I am assuming, it's not editable templates.Make sure:-1. your component does have a component group assigned2. your template does allow those components from design mode.

There is no way. except calling this include statement conditionally.That's the implementation for reference /libs/granite/sightly/templates/ClientLibUseObject.java

Nopes,AFAIK there is no OOTB way

You would need the knowledge of Java (not much in starting at least) for developing component, services and end to end working site.

Those are the way you can author content fragment.AEM 6.3 with a FP has introduced Content Fragment Models with which you can define your own structure for content fragment instead of just being rich text

It won't work, data-sly-resource gets compiled at server, so JS at browser wont have any control

Referring to the original implementation of styles plugin/libs/clientlibs/granite/coralui2/optional/rte/js/components/rte/plugins/StylesPlugin.js Configs are taken from styles node in the rtePlugins config in componentOverlay this file, have a separate node structure outside component to maintain cs...

Is it for dialog toolbar or inplace editing toolbar?

Integration is not available OOTb,but If omniauth exposed some endpoints, you can easily hook into Custom Login Handlerhttps://github.com/Adobe-Consulting-Services/acs-aem-samples/blob/master/bundle/src/main/java/com/adobe/acs/samples/authentication/impl/SampleLoginHookAuthenticationHandler.java