Sounds like you're just throwing shit at the wall and hoping something might stick and you get lucky. That's not a good way to look into the cause of any problem. Look at the symptoms to narrow down what the actual problem is first. Like, why try bump-starting it if the starter motor is turning the engine over already? They do the same thing and if one doesn't work, neither will the other. Not sure why you changed out the spark plugs. If they were sparking the night before just fine and the next morning they weren't, then the plugs aren't the problem and it would be more related to an ignition coil, not all 4 plugs. The overflow pipe from the tank is for fuel spillage and has nothing to do with the motor running. You could plug that hose or remove it all together and it won't affect the engine running. The vent line is different, but you can run it with the fuel cap open to resolve that if were an issue.
So, take a step back and look at the bigger picture. Ran fine one day and then overnight it won't start. The most likely thing that has changed is simplest. Check the sidestand safety switch. Since you put the sidestand down to park it, it is the only thing that really changed. But that should prevent the starter motor from operating at all. Just like the clutch safety switch. It might also be the fuel pump that is failed now and not providing the fuel pressure needed to run. Could also be the tip-over/vehicle down sensor. That typically causes the low oil pressure/FI warning light to flash when cranking the motor though. Dry, non-corroded connections doesn't mean anything. You have to check that the connections are touching each other correctly from one end to the other.
You shouldn't go shotgunning parts at this since changing so much can lead to other problems that you're not trying to solve. Start with the smaller, most likely fixes before moving on to the harder, less likely causes. The first step is to verify the safety switches are correct and not an issue. The next step is to verify the fuel pressure to the fuel rail and injectors. You can ignore everything else until you verified those things work properly.
