I don't know your plan specifics, but I'd install it with the included switch to start with. The last thing you want to do is mis-wire a Toyota switch and not know if the rest of the circuit is wired correctly while trying to debug the problem.
1) you don't. I'm now realizing it's probably been several years since I last had mine off, but I believe you just lift the console up and then rotate it 90 degrees to clear the shifter.
2) if there aren't existing connectors under there, then run a wire with a fuse as close to the battery as...