Turn it into the beginnings of a megacrossover by making it Emmett Brown instead of Emilius... or perhaps they're relatives. Mm. Emelius would have to be in his 90s by that point, anyway.
Hm. More ideas. One or more of the children took up the study of the Brown-Price style of magic, which is suspiciously like Will and Word in implementation. They'd be in their 60s by Harry's era, so they might be the Elders of a large clan of wandless magic users completely unknown to the Ministry... And perhaps the Wizarding World is completely unknown to them until they meet Harry... who shows a talent for their magic as well as Wizarding magic. And of course there's a rogue member of the clan who'll give the Ministry a justification for some overblown and violent reaction to discovering their existence, and who teams up with Voldemort...
Hm. Where could you take this from here?
-- Bob
---------
Then the horns kicked in...
...and my shoes began to squeak.
Hm. More ideas. One or more of the children took up the study of the Brown-Price style of magic, which is suspiciously like Will and Word in implementation. They'd be in their 60s by Harry's era, so they might be the Elders of a large clan of wandless magic users completely unknown to the Ministry... And perhaps the Wizarding World is completely unknown to them until they meet Harry... who shows a talent for their magic as well as Wizarding magic. And of course there's a rogue member of the clan who'll give the Ministry a justification for some overblown and violent reaction to discovering their existence, and who teams up with Voldemort...
Hm. Where could you take this from here?
-- Bob
---------
Then the horns kicked in...
...and my shoes began to squeak.