Issues with BerryBot Hardware

I am getting a BerryBot device ready to help my granddaughter with this learning experience.

My emails to you folks have yet to get a response, so I figured I would open a discussion here.

Issues listed below:

• If the motors are engaged at >10%, then the USB communication frequently drops out. More than 25-30% motor drive causes coms to drop out immediately. In my experience, this behavior is characteristic of a severe voltage regulation, or decoupling problem on the main board. Recovery typically requires a hardware reset, and a re-connect. I added a 47uF cap to the 3.3v header on the board, sadly no change in performance. Without a schematic, I have no plans to dig any deeper.
• If the motors are set to < 20%, then the wheels do not have enough torque to spin. They make noise, but that is all. This is disappointing, but not fatal. Clearly if there were wheel velocity sensors, and some simple PID control code, this would remedy this issue, but I understand that this would be outside of the scope of this introductory robotic toy.
• Although correctly wired, the tires spin incorrectly.  For now, Right causes Forward, Left causes Backward, Forward causes pivot Right, Backward causes pivot Left.  I edited the forward, backward, left, & right methods in the TB6612 module of the berrybot.py library. I'll need to edit other TB6612 methods in way as well, but this preliminary edit solved the problem for the method that I am currently using.
• Issuing a Stop from the IDE is most often ineffective, as with most of the above actions, using the motors appears to cause USB communication failures. Even without the use of the motors, the Stop from the IDE still appears slow and problematic.  
• Using Thonny, any of the code that employs motor control is at present is a waste of time, as USB communication is so frequently corrupted. Thonny throws exceptions similar to: PROBLEM IN THONNY'S BACK-END: Exception while handling 'Run' (ConnectionError: EOF). 

If the comm drop out issue is specific only to my board, then I will need a replacement assembly.

If this is an epidemic defect of the this first run of BerryBot devices, then this problem is magnified by the quantity of devices shipped.

What can we do to resolve these issues?  Thanks in advance for a prompt reply.