First of all aQ, wanted to acknowledge your success and thanks.
The main purpose of this post is to alert anyone still reading or coming across this issue of another bit of a problem. I JUST updated to the lastest Windows 10 release, 1703, the 'Creators update', which isn't quite being rolled out yet but can be obtained from MS right now. I've just updated (always a glutton for punishment but had been playing with the Insider Preview in a VM so was OK with it) -- so far so good, but my touchpad broke again, the same as decscribed in this thread.
Solution is the same and very simple, get into Device Manager, notice that the touchpad is showing an error, ask it to update driver selecting the I2C HID device, one quick click later the error goes away and the touchpad resumes functionality.
Note that in this instance that's it, no need (if there ever was) to get into the BIOS.
So what's going on here, despite any issues with the Acer BIOS, Windows just isn't setting up the device properly by default.