Hm. I suspect that all but Susan would be in Gryffindor, and Susan would be a Ravenclaw, and so alienated from her siblings. Although Edmund is more of a Ravenclaw than a Gryffindor, true. Although the cynic in me thinks the books would extol the virtues of Gryffindors and Hufflepuffs and unsubtly frown upon Ravenclaws' propensity for skepticism.

Eustace would probably be the good Slytherin.