[quote=Doctor Belasco]
How, incidentally, is Grant connected to the group? Everybody else seems to have a natural connection to at least one other person in the group (with the deliberate exception of Johann).
[/quote]

I presume he's naturally at least [i]acquainted[/i] with Logan due to both being Captain of their respective Quidditch Teams by their Fifth and Sixth year, and it seems practically the entire Hogwarts crowd was involved in the Dueling Club (I may or may not be removing that from Logan's history/credentials because of the oversaturation of members), with Emma being the Captain/best duelist amongst them. There's also a possibility of Johann having heard of the various Quidditch players of Hogwarts due to his own Quidditch prowess or an international school cup, heck, maybe even a Tri-Wizard Tournament. Unless of course those were just banned outright due to Darth Vadermort's reemergence during the one held in the 1990s.