  The supersymmetric SO(10) GUT based on the ${\bf{210\oplus 10\oplus 120\oplus
126\oplus {\bar {126}}}}$ Higgs system provides a minimal framework for the
emergence of the R-parity exact MSSM at low energies and a viable
supersymmetric seesaw explanation for the observed neutrino masses and mixing
angles. We present formulae for MSSM decomposition of the superpotential
invariants, tree level light charged fermion effective Yukawa couplings,
Weinberg neutrino mass generation operator, and the $d=5,\Delta B=\Delta L \neq
0$ effective superpotential in terms of GUT parameters. We use them to
determine fits of the 18 available fermion mass-mixing data in terms of the
superpotential parameters of the NMSGUT and SUGRY(NUHM) type soft supersymmetry
breaking parameters ($\{m_{\tilde f},m_{1/2},A_0,M^2_{H,\bar H}\} $) specified
at the MSSM one loop unification scale $M_X^0=10^{16.33} $ GeV. Our fits are
compatible with electroweak symmetry breaking and Unification constraints and
yield right-handed neutrino masses in the leptogenesis relevant range :
$10^8-10^{13} $ GeV. Matching the SM data requires lowering the strange and
down quark Yukawas in the MSSM via large $\tan\beta$ driven threshold
corrections and characteristic soft Susy breaking spectra. The Susy spectra
have light pure Bino LSP, heavy exotic Higgs(inos) and large $
\mu,A_0,M_{H,\bar{H}}$ parameters $\sim 100$ TeV. Typically third generation
sfermions are much \emph{heavier} than the first two generations. The smuon is
often the lightest charged sfermion thus offering a Bino-CDM co-annihilation
channel. The parameter sets obtained are used to calculate B violation rates
which are found to be generically much faster($\sim 10^{-28}\, yr^{-1}$) than
the current experimental limits. Improvements which may allow acceptable B
violation rates are identified.
