  Strengthening the synergy between simulations and observations is essential
to test galaxy formation and evolution theories. To achieve this goal, in the
first paper of this series, we presented a method to generate mock
SDSS-IV/MaNGA integral-field spectroscopic galaxy observations from
cosmological simulations. In this second paper, we build the iMaNGA catalogue
consisting of $\sim$1,000 unique galaxies from the TNG50 cosmological
simulations, selected to mimic the SDSS-IV/MaNGA-Primary sample selection. Here
we present and discuss the iMaNGA sample and its comparison to the MaNGA
Primary catalogue. The iMaNGA sample well recovers the MaNGA-Primary sample in
terms of stellar mass vs angular size relation and spatial resolution. The
S\'ersic index vs angular size relation, instead, is not reproduced well by the
simulations, mostly because of a paucity of high-mass elliptical galaxies in
TNG50. We also investigate our ability to recover the galaxy kinematics and
stellar population properties with full-spectral fitting. We demonstrate that
'intrinsic' and `recovered' stellar kinematics, stellar ages and metallicities
are consistent, with residuals compatible with zero within 1$-{\sigma}$.
Also`intrinsic' and `recovered' star formation histories display a great
resemblance. We conclude that our mock generation and spectral fitting
processes do not distort the `intrinsic' galaxy properties. Therefore, in the
third paper of this series, we can meaningfully test the cosmological
simulations, comparing the stellar population properties and kinematics of the
iMaNGA mock galaxies and the MaNGA observational results.
