Best way to get feedback from a user on a product?

The development team and I recently completed a new feature that was requested by a VIP-user at our company.

The product is not live yet, but still in development; my plan is to run the beta by the VIP-user to get feedback. The user might give design feedback, functionality (dev) feedback or a combo of the two.

The meeting will probably be short, like 30 minutes because the user is so VIP-busy.

I've been reading various things online about the best approach to this kind of thing. Just one example: https://www.nngroup.com/articles/designers-developers-doing-usability.

On one hand I tend to lean toward a developer/designer collaboration approach, but going alone seems easier to build a relationship (which, for me at least, is one of my main long-term goals). I also want to protect the development team from getting pressured into more development by a strong-willed VIP, but also see the advantage of having a developer in the room.

What are the pros and cons of going alone, going with others, devs, designers, PMs etc?