  We present new GRIFFIN project hydrodynamical simulations that model the
formation of galactic star cluster populations in low-metallicity ($Z=0.00021$)
dwarf galaxies, including radiation, supernova and stellar wind feedback of
individual massive stars. In the simulations, stars are sampled from the
stellar initial mass function (IMF) down to the hydrogen burning limit of
$0.08$ M$_\odot$. Mass conservation is enforced within a radius of $1$ pc for
the formation of massive stars. We find that massive stars are preferentially
found in star clusters and follow a correlation set at birth between the
highest initial stellar mass and the star cluster mass that differs from pure
stochastic IMF sampling. With a fully sampled IMF, star clusters lose mass in
the galactic tidal field according to mass-loss rates observed in nearby
galaxies. Of the released stellar feedback, $60\%$ of the supernova material
and up to $35\%$ of the wind material reside either in the hot interstellar
medium (ISM) or in gaseous, metal enriched outflows. While stellar winds
(instantaneously) and supernovae (delayed) start enriching the ISM right after
the first massive stars form, the formation of supernova-enriched stars and
star clusters is significantly delayed (by $>50$ Myr) compared to the formation
of stars and star clusters enriched by stellar winds. Overall, supernova ejecta
dominate the enrichment by mass, while the number of enriched stars is
determined by continuous stellar winds. These results present a concept for the
formation of chemically distinct populations of stars in bound star clusters,
reminiscent of multiple populations in globular clusters.
