If they have cracked already you need to get them in some soil asap. Don't know why folks need to complicate things by putting them in water like that. What's wrong with a moist towel or better yet, moist soil?
I'm sure I don't need to tell you this, but I am going to anyway. Why in the world would you go out and buy seeds, germinate them, THEN ask your friend's parents for permission to grow in the house?
Is there any way you guys could try to put them under some lights for a few weeks until it warms up enough to put them outside? That is still at least a month away in most parts of the US and Canada. At this point, it would be too long inside a house where the homeowners don't approve. I imagine you guys already went out and bought some equipment, right?