Using a development board to charge a lipo battery
The battery is connected to a different connector, not the same place as the input power. There is no pack balancing, it seems. It looks likely to work, and charge safely, but it won't balance the cells and this may affect pack lifetime.

The output from battery power through the buck converter is 6V rather than 5V. This is not ideal. You might be able to change this by altering the sense resistors on the board.

(4A seems rather high power consumption for a "tablet"?)