-snicker- I can just see that:
"Oh, and Minerva, dear, how is that young man I tutored doing over there? I so rarely see Tony Stark that I never hear how young Harry is."
Minerva's reaction should be priceless.
Author's response
I don't know how chummy Agatha would be, I see her as having an extremely low opinion of the culture that cast her out 300 odd years earlier...
Then again, who knows, I don't know how a scene will work out until I write it.