Question about using the ICSP Header

I recently built a 32 function button box using 6 momentary toggles, 8 momentary buttons and 4 rotary encoders.  Using a Leonardo board, I have had issues getting more than 28 buttons to work.  I have discarded 2 toggles  (on ) off (on) from my matrix which is now 4x4 instead of 6x4.  My question is, will Sim Hub recognize the MISO, MOSI and SCK pins on the header as digitial pin 14,15 and 16 per the Leonardo board?   I would like to wire the center pin of those 2 toggles to pins 14 and 15.   

Thanks,

James