1. May male heir will marry the daughter's kingdom of Aquitaine claimant. Only a strong claimant will be considered, as claim will become weak when he/she dies and his/her daugther inherits it.
Weak claims are inheritable once, and then not heritable (unless pressed somehow where they become strong and thus can be passed two generations as weak).
It's possible to find strong female claimants (if he has less than 3 boys) though weak claims work as well as you can form faction for those, so you could actually even form a faction to be ruled by the wife of your son (and prey for your son not to die from stress before he gets her pregnant with a boy

).
You can also scheme your way through pressing weak claims the conventionnal way (either through depose king CB if his heir is under age, either through the sneaky way murdering your way to a regency or female ruler).
Breeding claimant and pressing claim through faction is obviously the easier way as you can get people in your faction through spymaster, favors and alliances. If you're the kind of player with the ambitious trait though, you'll want to first press a claim the conventional way on a kingdom that is not your de jure kingdom, and then press a faction to put the new queen on the throne of your de jure kingdom. If you do it through your de jure kingdom, then you can't get her on another throne (unless you can somehow murder her way to inheritance).
If you do it with your kids instead of your wife though then it's another story as you can either get a kingdom per children Karling style (and get two for your heir the same way you can get two for your wife) or you can wait to die to press them when playing the guy with the weak claims. If you can get the AI to be stronger than your former liege though, there's a fair chance it will try to press its claims on its own.