Finally got the TinkerKit LCD module to work with MPGuino. As expected, substantial pin re-mapping was required. Also, it looks like the only button option available for the TinkerKit module is analog buttons. The traditional digital buttons (1 per pin) simply cannot be adapted.
Keep in mind that the below information in this here post is very preliminary, and may be subject to change.
The USB port on this module may be used as the serial datalogging output, while the TWI (either TWI1 or TWI2) pin0 (PD0/INT0) and pin1 (PD1/INT1) pins are going to be used for the fuel injector open/close sense pins. Digital port D12 (which is what is labeled on the module that I have in my hands) should really be labeled D11 (as it is in the picture). D11 (PB7/PCINT7/OC0A/OC1C) is going to be used for the VSS input. Analog port A0 (PF7/ADC7) is going to be used as the analog button input.
The serial port pin0 (PD3/INT3) and pin1 (PD2/INT2) might also could be used for fuel injector input, or it could be used for another serial port... perhaps for a secondary MPGuino display.
The TX LED is driven off of PD5/XCK1/CTS. The RX LED is driven off of PB0/PCINT0/SS. The S LED is driven off of PC7/OC4A/CLK0.
Analog ports A1 and A2 (PF6/ADC6, PF5/ADC5) are likely going for either the Chrysler MAP correction hardware, or for other analog voltage projects (vehicle battery, coolant temperature, or what have you).
Digital port D6 (PD7/OC4D/ADC10) apparently can also double as an analog pin, so this might could also be used for analog voltage projects.
Digital port D5 (PC6/OC3A/OC4A) appears to be a straight digital port.