I freely admit this doesn't directly answer your specific problem but I ran into issues with my Acer Chromebook 14 as well in Unity. Going with KDE instead worked better. If you're a Linux noob then switching environments isn't too big of a deal, right?
To install KDE, go through the same steps as using crouton for unity but the command to kick it off is
sudo sh crouton -t kde instead of
The keyboard works fine in KDE but the touchpad is still tricky. It doesn't need pressure as much as it needs finger surface area (using the pad of your finger rather than tip works). I'm digging through other Chromebook-touchpad-Linux threads to find a tweak that works to adjust the sensitivity.
Edit: Okay, I think I found the command to tinker with the touchpad sensitivity.
xinput set-prop "Elan Touchpad" "Synaptics Finger" aa bb cc
Where "aa", "bb", and "cc" are numbers. Mine had default values of 25, 30, and 0 which seem to translate as "low" "high" and "press" according to some X11 documentation I found. Using 5 10 50 worked alright for me. You may need to tweak those numbers. The important once is the "bb" value. It seems, as soon as it detects a pressure above "bb" it counts your finger as on the touchpad. So if it's not detecting your finger normally, lower "bb" until it does. Keep "aa" much much lower and set "cc" much, much higher so you can click with a tap.