His Shinigami powers are mixed with hollow powers in one Being( Hichigo who is the spirt of the big sword) and the small sword is his Quincy Powers ( Fake Zangetsu )I think one is hollow release and the other one is a shinigami release and there's going to be a 3rd Quincy release.
If you not read well, Ichigo now use the real powers , means now he use the inner hollow powers not the fake since fake is gone, so from now you will see the true power of Ichigo with inner hollow and for Tensa Zangetsu i doubt it was fake , there isnt him anymore he should use now as main inner hollowI re-read the chapter where Ichigo's Zanpakuto is reforged. Ichigo said the both are Zangetsu. And the guy how reforged asked him how those Zangetsu are? So it must be his shikai, because his bankai will be Tensa Zangetsu.