With the Tharness plugged in, and ONLY the RED connector on the evo plugged in, the car should be able to start with the key port. If it does not, there is a loose contact somewhere. Quick and easy is to replace the harness.
If you would rather test and isolate, follow the NON T-harness installation guide, as a reference, to test the harness. All connections in the wired guide, are what is within the harness. https://fortin.ca/download/72791/evo-all_ig_sal_bi_aud-a4-a5-q5-s4-s5_2009-2014_pts_a_72791.pdf
(keep in mind most resellers would not accept a return of harness that is tampered with, hence, replacing it first is a wiser option)
Asssuming that the car starts fine with everything connected , but, it does not remote start.
1. Check and test the brake connection. All three brake lights should be turning on upon remote start. Assuming that ignition is turning on, no ginition = no brakes = issue is elswhere.
2. RESET and reprogram module.
3. Try secondary CAN-BUs location. Above driver kick panel in a small brownish connector.
--- pic1 location, http://www.wirecolor.com/vehiclegroupimage/154617.jpg
--- pic2, http://www.wirecolor.com/vehiclegroupimage/106923.jpg