  Neutrino oscillation physics has entered the precision era and the potential
forthcoming experiments Hyper-Kamiokande and Deep Under-ground Neutrino
Experiment (DUNE) are expected to lead this endeavor. In this paper we perform
a comprehensive study of the octant, mass hierarchy and CP discovery
sensitivities of DUNE, T2HK & T2HKK in their individual capacity and
investigate the synergies of the aforementioned experiments with the on going
T2K and NO$\nu$A experiments. We present a comparative account of the
probabilities at the three baselines and explore in detail the physics issues
which can cause the discrepancies in the sensitivities among the different
experiments. We also find out the optimal exposure required by these
experiments for achieving $5\sigma$ hierarchy and octant sensitivity and to
discover CP violation at $3\sigma$ for 60\% values of $\delta_{CP}$. In
addition we vary the neutrino-antineutrino runtime ratios for T2HK & T2HKK and
check if the sensitivities are affected significantly due to this.
