Yes! The long single row header at the bottom of the board (GP0~GP25) gives you full access to all of the GPIO signal pins (3V3, 5V and GND are broken out elsewhere).
I2C-1 will be pins GP0 (SDA) and GP1 (SCL). SPI has two uses on this board; you can either connect the appropriate GP pins to the A/D+D/A headers with a few jumpers, or you can use straps to connect the GPIO SPI pins to the ATmega328P which allows you to program it directly from the Arduino IDE or a patched version of avrdude.
Basically, everything on this board is broken out and requires a bit of wiring to use. You can connect the 328P to the motor controller or buffers+switches+LEDs if you want. It’s totally, 100% flexible, which makes it a pretty powerful prototyping tool! :)