I wasn't super happy with how the vocal humming line gets a little lost inside the chords formed by other voices in m. 3-11, 35-38, 72-end. Since this is a vocal song and I think it would be good to focus on the humming, I might rework the part to place the hummed melody on top, and harmonize underneath instead of transcribing the voices directly.
I think this might work as is too, since the humming voices have the most colourful chord tones at the bottom, but I can see wanting to have the voice at top at some places.
-m17: The lyrics on beat 3-4 should be "sou da", instead of "so-u"
-m27: Maybe you could add a G-B dyad (or just a B) on beat 4 to resolve the Gsus4 from beat 1?
-m32 and 65: I think the lonely t from "hashitteku" should be with its other t on beat 1.5, I still hear the i on beat 1.
-m33 and 66: "surinureku" should be spelled as "surinukeru" instead (switching the r and k around)
-m41: I hear a few Eb's in beat 1-3 too, maybe you could add the Eb to the R.H. chord?
-m69: I think the u on beat 6.5 should be together with the o on beat 6, I think the singer just kinda reinforces the "ou" (from utaou) sound with a w. It doesn't sound like "o - u" at least.
-m43 and 45: I also hear a C in beat 4's R.H.
-m49: I mostly hear Fm here on beat 1 in the R.H., maybe Fm7 but not sure.