Any successful stories using a Captivate-created course during a virtual instructor-led training?

The answer to your question is YES, but it's not currently possible with default Captivate functionality.

As Lilybiri states, Captivate is designed for creation of course modules that a single user would consume, not multiple users all consuming and interacting with the same module.  For one thing, most LMSs would not be able to accommodate this because the LMS wants to track each user's interaction separately.

However, I happen to have inside knowledge that Tristan Ward from Infosemantics.com.au has been working with two separate clients who have engaged his services to create custom solutions to achieve what you describe. 

Each of these clients runs courses for multiple students at the same time.  Each student opens a Captivate module from their LMS, but the modules are also simultaneously communicating with another web-based database (Google Firestore) reporting the student actvity to enable them to all collaborate.  The instructor can see what everyone is doing in real time.

I need to emphasise that each of these solutions is customised to the requirements of the clients.  So this is not something that you can just purchase "off-the-shelf".  But it IS cutting edge and very cool to watch!

Not really sure that I understand what you are asking.

I always use Captivate to create a 'presentation' when I coach a webinar, workshop or training online. That presentation is set up so that it can easily be converted into an interactive tutorial as asset for the participants. That means mostly adding narration and explaining the interactivity.