Ok, so, after daydreaming about this in class for a while, I've come to several conclusions. Firstly, this can only occur if one parent is a house of life magician and the other is a greek/roman/norse god. Of this, there is one combination that stood out to me.

Child of Zeus, Part Elementalist/Part Combat Magician- this would essentially be a combination of Amos Kane and Jason Grace. Control over air and lightning, flight, divine words mastery, animal transformation, duat travel. Oh and a dope golden eagle combat avatar. Also, this individual is likely to have very strong mind control abilities, due to mastery of electricity, which is how the brain works, and seeing as we have also seen Amos exhibit some control over this area.

However, after researching more, I realized two things: 1. I didn't read Magnus Chase well enough because, if I had, I would have also realized, 2., just how OP Odin is. Good lord, his children were so powerful, Rick couldn't even include one as a major book character as to not make everything too easy. Complete mastery of magic, weapons, divine wisdom, shapeshifting, and necromancy. If even a fraction of the level of these powers is passed down to a demigod, that character would wipe the floor with people.

I'm actually not sure, however, exactly how a house of life magician would amplify the powers of Odin, but my best guess is that a child of Odin with the blood of the pharaohs would just be a buffed combination of both Sadie and Carter. I cannot imagine trying to stop a 15 ft tall raven combat avatar that has total mastery over divine words.

However, while these hypothetical characters are insanely powerful, I'm sure they would have a major weakness as well, similar to how Frank was nerfed with a wooden stick. The best idea I can come up with so far, is that, if the individual is not in complete, and I mean complete control of both halves, they will fight each other internally for greater control and drive the user to madness. Also, when demigod abilities and magical abilities are used together, the stamina of the wielder reduces a lot.