I agree that any work on the ground with Mango could be considered ground work at this point, whether it's lunging her or just petting her. She's getting used to be around the horse, and the horse is getting used to being around her. I agree--with her skill level, pushing buttons is probably a bad idea. But any interaction, no matter how non-trainy (yes, that's the technical term. ;) ), with the horse at this point is a learning experience.
For example: For the past month I've been working with a new horse. And while there are plenty of "real" groundwork sessions involving a round pen, a lead rope, and/or a lunge line, there are just as many groundwork sessions involving grooming, blanketing, and even just giving treats and being there. I'm learning about this horse, and in turn this horse is learning about me. The purpose for even these relaxed, informal sessions is that I want to know about her: What makes her start? When she does spook, how does she react? Do certain actions on my part make her anxious? Are there certain sensitive areas for her (for instance, I've discovered she doesn't like people messing too much with her ears and feet)? How does she react with other horses nearby? Is it different when she's by herself?
All of these subtle things help this filly and I to understand each other better, which translates into more productive sessions. And even if the OP isn't as advanced as someone else, I don't see why interacting with the horse in this level wouldn't be helpful either. If the horse hasn't been handled much lately, in fact I would certainly recommend starting with some basics and working up from there. It's learning to talk to the horses and listen to them that makes us better horse people in the end.