I went out and checked it again. It appears to be a pretty long pulse, like about 1/2 second. You can hear the solenoids engaging and then disengaging. They are all controlled by the same relay, so there is only one stage.
The lock side would look exactly the same as the unlock side, with a different color wire instead of the black one. With the same effort you could install two relays to flash the lights when locking it.
And, yes, that is what Relay 1 is for. Without that relay, every time you press the lock or unlock button inside the car, your lights would also flash. So you need the relay.
Unless, if that'* what you want, I'm not stopping anyone.