  We follow our first paper with an analysis of the ensemble of the extensive
pre-explosion ground- and space-based infrared observations of the red
supergiant (RSG) progenitor candidate for the nearby core-collapse supernova SN
2023ixf in Messier 101, together with optical data prior to explosion obtained
with the Hubble Space Telescope (HST). We have confirmed the association of the
progenitor candidate with the SN, as well as constrained the metallicity at the
SN site, based on SN observations with instruments at Gemini-North. The
internal host extinction to the SN has also been confirmed from a
high-resolution Keck spectrum. We fit the observed spectral energy distribution
(SED) for the star, accounting for its intrinsic variability, with dust
radiative-transfer modeling, which assume a silicate-rich dust shell ahead of
the underlying stellar photosphere. The star is heavily dust-obscured, likely
the dustiest progenitor candidate yet encountered. We found median estimates of
the star's effective temperature and luminosity of 2770 K and 9.0e4 L_Sun, with
68% credible intervals of 2340--3150 K and (7.5--10.9)e4 L_sun. The candidate
may have a Galactic RSG analog, IRC -10414, with a strikingly similar SED and
luminosity. Via comparison with single-star evolutionary models we have
constrained the initial mass of the progenitor candidate from 12 M_sun to as
high as 14 M_sun. We have had available to us an extraordinary view of the SN
2023ixf progenitor candidate, which should be further followed up in future
years with HST and the James Webb Space Telescope.
