A question came to me while reading this; is it inferrable that Ice Ages on other planets would not have occurred save for a Lavoid's impact? Ones unafflicted by Lavoids may have Reptite or Dragonian similar lifeforms. Also, it is said in Cross that humans did not evolve into intelligent beings until after contact with the Frozen Flame; is it neccessarily a fact that a Frozen Flame splinter of a Lavoid's shell occurs with every landing? The Chrono world may be very unique in its universe.
Given that Ice Ages appear to be a phenomena that occurs in reality as well, I don't know if we can assume that
all Ice Ages in the Crono Universe are brought on by Lavos. I think we'd need to see a more in-depth explanation of Crono's planet as well - 65,000,000 years is a long time for a single Ice Age and seem to remember reading theories here that suggested that only the initial period was brought on by Lavos. (Not sure what I personally think about that.)
Who knows what other races lie out there. Perhaps that's where the series will go next?
Not to mention that if there are other Lavoses, then there could also be other beings on the same scale as the DoT.
That's a scary thought. Perhaps another "Lavos Invasion" is still very possible? I don't know about the likelyhood of another Time Devourer, though - that was born under some very unusual circumstances. It might be possible, but seeing that trick again in a later game might be a little bit of a rehash.