Consider the factors of time travel and the effects had by Crono and Co. in Chrono Trigger. Did they truly travel in time more than once? Or, did they, in fact, travel across a series of alternate realities without knowing that they had done so?
If Crono and Marle/Nadia had not traveled in time from the Leene Fair in 1000 AD, would Lavos have come to Earth at all? Such a beings' feasting on knowledge and absorption could not have destroyed the world on its own, as evidenced by the emergence and rage of Lavos in 1999 AD; creating an apocalyptic destruction. In correct terms, this insinuates that Lavos was absorbing information and data from countless entities throughout time and space within the confines of the Earth without harming it. It can be considered, at that point, that Lavos was only thought to be evil based on reactions by Zeal, who wished to harness the powers of Lavos for evil; Janus, who wished to avenge Schala and get her back and, as a child, misperceived the events that occurred involving Lavos; and Crono and Co. themselves as they interacted with time and saw the Lavos attack of 1999 AD and assumed that Lavos was evil.
Furthermore, it must be considered that Lavos did not come to Earth simply to absorb the information held just by the inhabitants of Earth, but due to the ready supply of the timestream itself and all data of the flowing of time, as reinforced in Chrono Cross when Lavos does not simply exist throughout one timeline, but two.
It is my theory that without time travel at all, Lavos may not have seen fit to come to Earth, since the energy alone of the creatures there and their learning and knowledge may not have attracted it. Therefore, without the initial time travel by Marle/Nadia and Crono in 1000 AD, Lavos would not have been on Earth, or at least would not be known to be in the Earth; and the destruction of 1999 AD may have been able to be avoided.
Beyond that, Crono and Marle/Nadia would not have disappeared for days, but would have had a pleasant time at the fair before she returned home; Crono would possibly not have gone to jail, they might possibly have had further dates and Crono would still have wound up as the King of Guardia in a Queendom; not a Kingdom.
However, the ripple effects of time did attract Lavos to the scene from 1000 AD, hence why the story opens there, and attracted it to Earth well before this ripple ever began, back in the age of the dinosaurs. How can something that hasn't happened yet cause something to happen that will cause it to happen?
It is believed that the sheer potential of a reality and universe, from its very beginnings, causes all of time and space to exist. From nothingness itself, the universe and reality can spring into existence just by the sheer potential of what it could be if it did exist, causing it to bring itself into existence in a variety of 'impossible' ways, from the inside out.
Therefore, we can ascertain that there was a reality where there was not any time travel, no travel between alternate realities and no Lavos. However, due to what was that caused the existence of their reality and their universe, there were grooves in the track of existence; ruts; that caused the overlay of reality wherein time travel became a possibility and eventually a reality, bringing Lavos to Earth to learn, not destroy; causing the confusion inherent in the inhabitants of Earth, causing the corruption of Zeal already fat on magic to begin to be greedy for more, causing Crono and Co. to go through and destroy Lavos, which caused the reincarnation and the passing of information on to the Lavos in Chrono Cross.
From the very beginning, with the first time travel by Crono and Marle; they returned to an alternate reality from when they left with a variety of possibilities of how it could have turned out: The one I already detailed where they did not travel through time at all; one where Queen Leene dies and Marle/Nadia is subsequently wiped out of existence or placed beyond their ability to remain a part of the ruling family of Guardia, however still present in another place in the world; the death of Crono and Co. before they go on their journey to learn of Lavos and to 'destroy' the invading parasite/symbiote; Lucca not showing up in the past due to something preventing her from figuring out the secrets of the gate key and Crono remaining lost in the past, etc.
Each of these possibilities creates an alternate reality spin-off from the main reality, which does involve time travel; it must for the story to exist, for the reality to exist fully. At each point of the 'game', there becomes these varied, strong, possibilities branching off to create fully-fleshed alternate realities of their own. And, several weaker possibilities throughout the lives of all those who inhabit the Earth that do the same, creating a vast array of alternate realities for each one, for each moment of their lives with separate time lines altogether; with groups from one reality in another without the rest of singular individuals existing in a world seemingly all their own away from the others that inhabit the main reality; and that between these extremes, a whole vast palette exists for each entity and living thing on the planet and furthermore, for each thing in each alternate reality as well; throughout the entire length of the existence of the planet, including Lavos.
This is pertinent to understand because, on some level, some of those lines begin to attach to our reality and hence our knowledge of the world within Chrono Trigger and Chrono Cross, delivered to us as a game, written by story-tellers and dreamers and constructed by artists, seers.
furthermore, each weaker reality that exists serves to reinforce the main reality; the multiverse/multireality and the omniverse/omnireality and will eventually; even if able to stand away without merging with the main reality; will eventually be drawn into and merge with the main realities which will in turn merge with the main reality. Note the difference between the plural and the singular.
At the same time, Gaspar's 'End of Time', is not a place without time, but with a timeline of its own, and is it truly the 'end' of time? Or, is it merely a pocket eternity all of its own, transcending time as it appears to do? A place where nothing was and then something, with the first intrusion: Gaspar. Nothing does not remain nothing for long. A pocket of time and space; much like a black hole, or a secret niche that becomes less secret the more that others know about it.
I can and will expand on this later, but I need time to let my thoughts regather and to see what others have to say or add to this.