Neville shrugged helplessly. He was still wondering about the Potters. Wizarding families did intermarry all the time, it wasn't totally implausible that somewhere sufficiently far back on the family tree for someone to have forgotten about it there was a male Potter squib that hadn't been killed (because the Potters were exactly the sort of people not to disown their Squibs) and who'd had Muggle kids and then some number of generations later a Muggleborn with a different name had shown up in that line, and since they had magic they'd technically be eligible to inherit if the main branch all died ...