  We present a systematic numerical-relativity study of the dynamical ejecta,
winds and nucleosynthesis in neutron star merger remnants. Binaries with the
chirp mass compatible with GW170817, different mass ratios, and five
microphysical equations of state (EOS) are simulated with an approximate
neutrino transport and a subgrid model for magnetohydrodynamics turbulence up
to 100 milliseconds postmerger. Spiral density waves propagating from the
neutron star remnant to the disk trigger a wind with mass flux
${\sim}0.1{-}0.5\,{\rm M_\odot/s}$ persisting for the entire simulation as long
as the remnant does not collapse to black hole. This wind has average electron
fraction $\gtrsim 0.3$ and average velocity ${\sim}0.1-0.17\,$c and thus is a
site for the production of weak $r$-process elements (mass number $A<195$).
Disks around long-lived remnants have masses ${\sim}0.1{-}0.2\,{\rm M_\odot}$,
temperatures peaking at $\lesssim10\,$MeV near the inner edge, and a
characteristic double-peak distribution in entropy resulting from shocks
propagating through the disk. The dynamical and spiral-wave ejecta computed in
our targeted simulations are not compatible with those inferred from AT2017gfo
using two-components kilonova models. Rather, they indicate that
multi-component kilonova models including disk winds are necessary to interpret
AT2017gfo. The nucleosynthesis in the combined dynamical ejecta and spiral-wave
wind in the comparable-mass long-lived mergers robustly accounts for all the
$r$-process peaks, from mass number ${\sim}75$ to actinides in terms of solar
abundances. Total abundandes are weakly dependent on the EOS, while the mass
ratio affect the production of first peak elements.
