If I configure the FX3 as 32 bit wide synchronous slave fifo do I still have access to GPIO pins 50 - 57.
Page 33 of the CYUSB3014 data sheet suggests that these pins are assigned to the I2S and UART functions when in 32 bit slave fifo mode. Can these pins be forced to GPIO?
Yes. You should be able to use it as GPIO.
The datasheet is missing the first 3 headings for that section. I've informed the concerned team, we should be updating it in the next revision.