It wouldn't be my first choice to use the 2225H in Cubo Kick 18 but it can be done, it's Xmax is on the small side for Cubo 15 so Cubo 18 is abetter choice. If the 3 cm depth difference is that important you could add 3 cm to the front of Cubo Kick 15. Alternatively you could also use the 2240H in Cubo Kick 18.
Both 18's drivers are suited for Cubo 18 Extended. The 2242H will take the most power as it has plenty of Xmax, for the 2240H I would use a 40 Hz high pass and around 500 W of amplifier power as it's Xmax is somewhat limited.