Since there are no replies, I'll go ahead and address it. Chrono Cross (well, the lost timeline) seem to suggest that Lavos's evolution at this point is now a matter of harnessing Arbiters to gain enough energy or something else to mature and cause the destruction of space-time.
Evolving in the traditional format sort of seems moot at this point. It's suggested that the Time Devourer needs Serge, or at least needed Schala in order to mature...that it needed these individuals despite the fact that under your model, it would have had access to trillions more.
Finally, there's no basis for those dead timelines being accessed, manipulated, or experienced save for the resurrection of Lavos's destruction in Home World's future. Still, that's a special case; they probably meant that Serge just caused destruction over again instead of resurrecting a specific timeline. As for the theory that Lavos gets to the DBT exactly because his pocket dimension timeline is negated and sent there, implying that there is a corporeal existence after such a thing, well...the PD theory isn't too healthy these days, and it's about to be reevaluated or seriously modified. How Lavos got there is an enigma.