Edit: best known is 96 half-moves by Friedrich Burchard & Friedrich Hariuc (1976). (link to answer)
My best score 104 half-moves:
1.a4 b5 2.a5 b4 3.a6 Bb7 4.axb7 h5 5.bxa8=Q h4 6.g4 h3 7.Bg2 hxg2 8.Ra3 bxa3 9.b4 gxh1=Q 10.e4 a2 11.b5 a1=Q 12.b6 a5 13.b7 d5 14.c4 Nd7 15.c5 Nb6 16.cxb6 Rh5 17.gxh5 g5 18.h6 g4 19.h7 g3 20.h4 a4 21.h5 a3 22.h8=Q a2 23.h6 axb1=Q 24.h7 g2 25.Bb2 d4 26.Bc3 dxc3 27.d4 c2 28.b8=Q c1=Q 29.b7 e5 30.Ke2 c5 31.Nf3 c4 32.Qba7 Bc5 33.dxc5 c3 34.Nd4 exd4 35.f4 Kd7 36.e5 Ne7 37.f5 Ng6 38.fxg6 f5 39.g7 f4 40.g8=Q Qca3 41.c6+ Ke7 42.e6 Kd6 43.c7 c2 44.Qhg7 c1=Q 45.Qc2 d3+ 46.Kf3 d2+ 47.Ke4 d1=Q 48.c8=Q f3 49.e7 f2 50.e8=Q f1=Q 51.h8=Q Qc7 52.b8=Q g1=Q+
Conclusion: it is impossible to make it in 80 half moves as it is required to bring the king to safety and in order to make some pawns swap files, you need to sacrifice minor pieces (at least some of them must not remain in their original squares).
I think it can be improved, but not that much.
Also, yes, the type of promotion affects makes the output differ because queens cover much space and you need to protect the king.