Finally got the parts and some time to test out the circuit. I got STU85N3LH5's in the end. After a couple of hours of hiccups I can glady say its working 
first I had a strange ground problem that was the cause of some very weird behavior and then I hooked up the 74HC240 not realizing that the pin out is such that the inputs are staggered from side to side of the device 
Thanks David as always! That should be the hardware aspect sorted so I can start building it and using all the channels I will need