  We present spaxel-by-spaxel stellar population fits for the $\sim$10 thousand
MaNGA datacubes. We provide multiple extension fits files, nominated as
MEGACUBES, with maps of several properties as well as emission-line profiles
that are provided for each spaxel. All the MEGACUBES are available through a
web interface (\url{https://manga.linea.org.br/} or
\url{http://www.if.ufrgs.br/~riffel/software/megacubes/}). We also defined a
final Active Galactic Nuclei (AGN) sample, as well as a control sample matching
the AGN host galaxy properties. We have analysed the stellar populations and
spatially resolved emission-line diagnostic diagrams of these AGNs and compared
them with the control galaxies sample. We find that the relative fractions of
young ($t \leq $56 Myr) and intermediate-age (100 Myr $\leq t \leq$ 2 Gyr) show
predominantly a positive gradient for both AGNs and controls. The relative
fraction of intermediate-age stellar population is higher in AGN hosts when
compared to the control sample, and this difference becomes larger for higher
[O III] luminosity AGNs. We attribute this to the fact that extra gas is
available in these more luminous sources and that it most likely originates
from mass-loss from the intermediate-age stars. The spatially resolved
diagnostic diagrams reveal that the AGN emission is concentrated in the inner
0.5 $R_e$ (effective radius) region of the galaxies, showing that the AGN
classification is aperture dependent and that emission-line ratios have to be
taken together with the H$\alpha$ equivalent width for proper activity
classification. We present a composite ``BPT+WHAN" diagram that produces a more
comprehensive mapping of the gas excitation.
