Handling the new School Adept feats

So, the AU School Adept feats (ie, Enchantment Adept) always prepare a list of 5 spells, assuming you have spell slots of the appropriate level.  But it never adds those spells to your class spell lists, nor does it make you choose an attribute as your casting stat.

There is no RAW here, the rule is literally not written which would answer these questions, so what do people feel is the best houserule for handling these feats?

1. Choose an attribute.  These spells are cast using that attribute.  (OR use the attribute improved by this feat would fit here, too.  Operates like Fey-Touched or similar.)

2. Add these spells to your class list(s). (Works like Eberron Dragonmark spells.)  You cast like your class.  (If multiple classes, can choose when you cast).

3. Something else?