The analytical modeling for channel linear and non-linear impairments (LNI) and simulative analysis of extended power budget class-1 i.e. E1-class of next generation passive optic network-2 (NG-PON2) delivering symmetric 2.5 point-to-multi point (PtM) representing time and wavelength division multiplexing (TWDM) XGS-PON along with 10 Gbps point-to-point (PtP) wavelength division multiplexing (WDM) symmetric and coexistent channels in worst-case scenario is presented in the paper. Channel modelling of LNI is carried out under the incremental and aggregate strain of estimated chromatic dispersion CD, selfphase modulation (SPM), cross-phase modulation (XPM) of single mode fiber (SMF) channel deployed in optical distributing network (ODN) between 20 – 50 km link lengths. Downlink (D/L) and uplink (U/L) ODN is optimized to PTODN = 7.1 dBm and 4.09 dBm respectively and corresponding channel imparities including Kerr parameter γ, corresponding SPM, XPM, CD, four-wave mixing (FWM) analysis and corresponding component power and efficiency, interchange crosstalk (Cc) attracting power penalties (Pc) are estimated and incorporated in the simulation for the real response of lossy SMF channel. Further, splitter power budget (SP) and slitter configuration for respective PtM and PtP D/L channels are estimated under the aggregate impact of CD, SPM, XPM and FWM. Analytical modeling of LNI and simulative analysis has confirmed the configuration delivered rise in receiver sensitivity (Rxs) of -39.75/-33.45 dBm and -29/-35.34 dBm for D/L and U/L channels respectively. The estimated power of FWM element is between 1.34x10-52 to 2.15x10-53 and 3.87x10-52 to 2.41x10-51 contributing crosstalk between channels (Cc) of -31.97/-30.12 dB for down/up spectrum under the impact of SPM and XPM respectively accommodating splitter configuration of 768 at 40 km.