I've taken one of the charmed minor characters kids, except he turned into a bit of a crazy combination of both fandoms.
His father is Simon Marks - from charmed - The british guy who came to try and claim Paige as his future wife after she had already met Henry. And his mother is Daphne Greengrass - From HP - so that Simon would have still found a good standing family to marry.
You might want to look at the histories here. I did my best to meld the two worlds.
OH! and Kat and Courtney, Since I made Simon marry Daphne Greengrass, Trent's family to Astoria and Scorp.
Please ask me any questions you might have. It might help me get rid of some of the problems I had melding the two worlds.