This is most definitely an interesting thread. I'll keep an eye on it.
I've been researching the pas couple of months about the remote start systems and the installation process and such as I will be attempting to install one after a couple of months when I finish my University studies and and get back home.
One important part that I see missing in your logic is, as you said, related to the wires going all the way up to the cylinder.
If I remember correctly, those wires are there to check if the key is in the crank position. I'm not entirely sure about this, but AFAIK you can bypass that by turning the key to the crank position and check what resistance it's providing. Then all you'd have to do is connect an equivalent resistor to the harness and voila! (not entirely sure about this theory, but I believe that should be it)
The bypass module that is needed for remote start systems is used to mimic having the key inside and allows the car to run.
For testing this, I would highly suggest removing the ignition switch, and then using a key turn the teeth twice to mimic going to the run position. Keep it in that position and put your key in the cylinder and turn the key all the way to the cranking position. At this stage (or earlier), disconnect the wires going to the cylinder and check what resistance is it's resistance that'd be the resistor you need to buy. But before pulling the trigger, just as a proof of concept, reconnect the cylinder wires and try to start it using the push button theory that you tried earlier.
The only difference between this state and the state that you tried before is that now they key is "seen" as being in the crank position. If it starts then all you have to do is put the aforementioned resistor in the connector of the cylinder and call it a day.
I, for one, was fiddling around with the ignition switch one day, and turned the teethe of the ignition switch all the way to crank, but the car wouldn't start unless the key is in the cylinder AND turned to the crank position. I'm not sure however, if I tried while the key is in any position other than crank. That was a like 9 months ago.
Keep us updated!
Regards,
H4L