I’d say that planning to be cash poor but house rich by the time your kids reach 17 is bad idea. But that’s just me. I have no kids.

In order to be house rich (i.e. have a large mortage) you have to have pretty good income. If that’s the case, your kids are unlikely to get grants. They’ll get loans which they’ll have to pay back. Better to teach your kids so they are smart and get full scholarships.