refined/groomed/point estimated during the current sprint without for the Product Backlog Refinement call

There's no defined method or process for refinement. It's not one of the Scrum Events defined in the Scrum Guide. The team can determine when and how to refine Product Backlog Items and what is required for a Product Backlog Item to be considered ready for selection in a Sprint.

As far as pulling in work, Developers can pull in work if they have the capacity to do so. However, my advice is usually to pull in new Product Backlog Items as a last resort. There are likely better opportunities to help other people on the team get work to done, to promote cross-functionality, or to take on "overhead" work. Starting new work can be risky, especially if there's no guarantee that it will be finished, because unfinished work is waste.

Can the stories be refined/groomed/point estimated during the current sprint without for the Product Backlog Refinement call? Developers are looking to pull in prioritized stories as they have bandwidth.

If they've met their Sprint Goal they can do whatever they want, but it might be a good idea to see how well the current Increment meets stakeholder needs before any new work is assumed.