Master - Slave Batteriemanegement System using LTC6804-2

I want you to build a Batterie Management System using the LTC6804-2 IC. The LTC6804-2 handles up to 12 cells, so we need a Master/Slave System. S1 to S12 from the LTC6804-2 shall not be connected all the time. If the cells have to be balanced, there should be another PCB which has an external discharge circuit on it, which is controlled by the LTC6804-2. The master unit shall request and receive all the data from the slaves (but that actually explains itself). It's coupled to the slaves with a LTC6820. The master then shall process all the data, calculate values like -State of Charge -State of Health -Internal resistance if each cell -etc.. Additionally it has to control (simply turn on and off) the charger and display the desired values in a GUI. I don't want the master unit to be an Arduino board, because it has to be failsafe. I am open to suggestions…especially regarding the GUI and the way how to setup the values (high voltage, low voltage, temperatures, currents, etc.)