One of the three fundamental flaws to all the ‘theories’ you have just pointed out.
1) There had to be something there to explode.
2) The laws of physics have to be suspended for the explosion to occur. There is this little thing called an event horizon that has to be surpassed before matter could actually get out of the pull of the supermass. Otherwise, you have the ‘Big Puff’ not the ‘Big Bang’. However, all the scientific ‘evidence’ to the length of this time of no laws/reverse laws is still not long enough before the event horizon to kick in and suck everything back in.
3) The original poster’s comment about water is part three of the three flaws. The spinning velocity needed for the Earth to form from gas is too fast for water to have remained on the exterior of the surface, and not instead be trapped in the interior.