Show custom sidebar only in archive page of specific CPT only for specific tag

Hello @jotomas,

Is it possible to show a custom sidebar only in archive page of specific CPT only for specific tag?

Not exactly. It will allow you to select sidebar for specific archives, however not for specific taxonomy terms like tag.
But you can do that with the visibility option for the widget itself:

If the sidebar contains only a text or html widgedt with a shortcode of a third party plugin, will this shortcode be executed?

Sidebars created with Custom Sidebars plugin are working exactly the same as sidebars that come with your theme. So if shortcode is executed with theme sidebar it will be executed with the custom one.

Is it possible to have a custom sidebar as a shortcode?

At the moment it is not possible.

Is the Pro version required for some of these functionalities?

No, Pro version works exactly the same.

kind regards,
Kasia