This frozen cursor in top left problem happened to me with Ubuntu 16.10 using a GTX 1070 in a desktop as well. I made it through the installation using the keyboard. Once I installed the nvidia-367 binary drivers the problem went away.
I ended up needing Ubuntu 16.04 for what I was doing and the cursor always worked during installation of that version.
This frozen cursor in top left problem happened to me with Ubuntu 16.10 using a GTX 1070 in a desktop as well. I made it through the installation using the keyboard. Once I installed the nvidia-367 binary drivers the problem went away.
I ended up needing Ubuntu 16.04 for what I was doing and the cursor always worked during installation of that version.