Does Dev team required in PBR meeting

First question, what does the team think of this?

Second question, what is the difference between refinement and grooming?

Third, what is meant by "lock"?

But to sum it all up... what is the purpose of product backlog refinment, and how does the team think transparency, collaberation and inspect & adapt are best served?

Additional questions to Xander's:

• What is your role for this team?
• Would transparency (i.e. we need to understand and know what is going on) be lost for the Development Team if they didn't attend those meetings? 

In addition to the questions by Xander and Chris, I'd point out a few things.

Scrum doesn't require a refinement meeting. The methods to perform refinement are left up to the team. There may be meetings involved or there may not be. The teams that I work with tend to include a meeting, either to do refinement as a group or to regroup on refinement work that has been done by subsets of the team and get everyone aligned.

It's not clear to me what the difference between "refinement" and "grooming" is. The Scrum Guide uses "refinement" now because of the connotations associated with "grooming" in some parts of the world. The Scrum Guide also states that Product Backlog Refinement is a collaborative effort between the Product Owner and the Development Team. It does not preclude the inclusion of other stakeholders and there are other discussions here (and probably in other places as well) about including others in refinement activities.

You may be interested in Three Amigos sessions. It's not exactly what you describe, but the idea of getting input from the Three Amigos (the perspectives of development, test, and business) prior to involving the whole team in refinement is not uncommon. This can help address glaring issues or questions early with a few key people to let the others make more effective use of their time.

I would like to know do I need to involve dev team in PBR meeting?

What does the Scrum Guide say about who collaborates in Product Backlog refinement?

Also, if an MVP is "locked" for upcoming Sprints, what purpose would it (or the Sprints) then serve?