1. Ours are RNP5. Dunno about the newest airframes from Touluse
2. 42-500 has no problem to climb FL250. The 72 struggles but it's possible if low SAT/light a/c. Heard of ferry flights up to FL300, but never tried and doubt it's legal
3. Switch the Yaw damper back on? I don't think there's any special technique...
Cheers!
Stuck