Alas you all could of said this already, but its so hard to find what your looking for with the search engine.. so!
Playing CT, and reading everything on Time Error and Lavos's pocket dimension and whatnot, i got confused!
In the ocean palace disaster, Lavos seems fully matured, at a state like when you defeat it, but did Lavos not come to earth as an infant, or Lavos Spawn, correct me if im wrong there because that will probably put all this to rest.
If Lavos's pocket dimension runs on a timeline parrallel to the planets, then surely there must be a timeline for the planet for every second or millisecond (or something of the like) that Lavos is sucking out the planets enegy's.
For example when lavos first arrives on the Earth surely Zeal will not of noticed the large powers of Lavos and it would not have said large powers, and as such would never bother making the mammon machine and the entire Ocean Palace scenario would of been averted, as would the apocolypse, hell the planet would likely be completely diferent.
When Lavos gets enough power for the Zealians to realise, they start up with the mammon machine and ocean palace scenario, although depending on how much power Lavos actaully has at this stage it may not be able to defeat the Zealians, though this seems incredibly unlikely as it would definetly of stopped the Zealians stealing his power or he would of never got to the stage you see him in playing CT (Heh, just realised i keep swapping between it and he when refering to Lavos, apologies).
And one final sidenote, after Crono and crew defeat Lavos, and Belthesar does all his work in time travel and Chronopolis, etc. Why doesnt he try going back in time to when Lavos was landing, as he presumably was in 'Planet Time' during this, and try stopping Lavos from landing or burrowing, i admit it may be hard.. But surely he could time travel far to the future or something and get the technology required for this. If they did so, would it not completely avert the entire events of CT, CC, and RD.