AS you specified - this looks like a lib conflict on this specific instance. A fresh instance - as you said  - you are not seeing this behavior.To get more background - did this start happening all of a sudden or after a new package was installed.

So in your experience - Touch UI works better --- "We can select multiple Styles for same selected text in Touch UI RTE."This is to be expected as Adobe is no longer investing in Classic UI. Adone recommends using Touch UI as much as possible. This is best practice.

Can you please post a screenshot of exactly what you want to do. Seems like you want a link on page properties dialog that downloads a file.

Can you post a screen shot of your dialog to make this clear.

According to the AEM Docs - there does not appear to be a way. See here for inheritance information - Developing AEM Components

Gaurav is correct - this functionality is not available OOTB. When an author creates a page, they must select a template - which should be an editable template. Template authors have the ability to create template with policies, fixed components, layout container (which container author able compone...

I am checking too if this is a known issue.

This certainly should not be happening. As you know - as soon as you a component onto a page - the component should be visible immediately. Are you seeing any log errors or browser errors.

Team replied: "there is a delete but you can’t delete the master variation. They should see the delete button on other variations or if they go up to the parent of this node"

Is this behavior observed in only this component or in all custom TOUCH UI components. Are you seeing any browser errors?This should not be occurring.