Hello ! Thanks for your interest in Pinocchio.

If you have a floating-base robot defined using the free-flyer joint model, then the corresponding part of the $q$ configuration vector is actually the xyz for the base position followed by the 4D quaternion corresponding the orientation of the robot (so, not the Euler angles). Notably, this means the part of $q$ you want is actually qPinocchio.head<7>(). Pinocchio does not use Euler angles, but the appropriate double-covering quaternion representation (although you can convert between these representations using tools provided in the library).

For the velocity and acceleration vectors $v$ you'll get the 6D $(v_x,v_y,v_z,\omega_x,\omega_y,\omega_z)$ spatial velocity from vPinocchio.head<6>().