Quantum calculations of spatial distributions and angular momentum polarization (orientation and alignment) of the fragments in the photon-induced vibrational predissociation of Ne...ICl and Ne...Cl2 van der Waals complexes are presented. The general theory of vector correlations in photodissociation is particularized to the case of slow photopredissociation where the lifetime is long compared with the rotational period of the molecule. The formalism is applied to Ne...ICl and Ne...Cl2 using empirical potentials determined before. Photodissociation line shapes have been computed by 3-D converged integration of the close-coupled vibrational and rotational equations. Vibrational predissociation line widths, final rotational-state distributions (scalar properties), and spatial anisotropy parameter of the angular distribution of the fragments as well as the orientation and alignment of the rotational angular momentum of the diatomic fragment (vectorial properties) have been calculated. The results are discussed in terms of the symmetry properties of the transition dipole matrix elements and the ro-vibrational dynamics during dissociation. In particular, the role of the mixing of final channels with different helicity quantum numbers (the projection OMEGA of the total angular momentum J on the dissociation coordinate) is stressed. It is found that vectorial properties are much more sensitive than the scalar quantities on the detail of final-state interactions and Coriolis couplings. A diabatic vibrational golden rule (DVGR) treatment and an infinite-order sudden approximation (IOSA) of the rotation in the final vibrational channel channels have also been implemented and checked against the converged full line shape calculations. It is shown that while DVGR is an excellent approximation for both scalar (lifetimes and final-state rotational distributions) and vectorial properties, IOSA is very poor for describing the latter.