1) Daniel lived happily on Abydos with Sha’re and their 9 week old daughter when the SGC sent their message through the Stargate and subsequently came through to visit. The planet wasn’t visited by the Goa’uld and he chose to stay with his family rather than to move back to Earth. However, Jack was able to convince Daniel to work as a linguist for the SGC in exchange for water and medical aid for the Abydonians. Over the years he would occasionally join SG1 on archeology-related missions, or simply visit Earth to show Sha’re and his family his homeworld.
This reality never befriended the Unas or the Asgard, nor did they find the Replicators or Atlantis. They were, however, conquered by the Ori.
Luckily the SGC were able to open the Gate one last time and several hundred people were able to flee to Daniel’s new homeworld before the old one was blown to pieces by Earth’s planetary self-destruction.
2) Sarah Gardner didn’t give up on Daniel, instead she worked alongside him. She managed to convince him to write a book about his theory that the pyramids were landing platforms for spaceships, rather than to present it for their peers at the discourse.
The book included color photographs of many texts and pictograms and a word-by-word translation of each to prove his theory. The book became a bestseller and spawned several sequels, but he was still laughed out of academia. He still received several major grants from private benefactors to lead four digs in Egypt at the Giza Plateau. There was always someone who was willing to take a chance on the unlikely despite the overwhelming odds against it, especially if there was a chance that it could earn them wealth and fame.
Several years after the initial book was released he had a major breakthrough, unfortunately it was in the form of finding two intact stasis jars. By the time they realized what had happened Daniel was host to Osiris and Sarah was host to his queen Isis.
3) Egeria’s First Scholar, a Tau’ri slave named Daniel, had quickly risen in the ranks of the supposed Goa’uld queens court as he were able to translate texts that had mystified the Goa’uld for several millennia. In an effort to retain his knowledge for as long as possible she had convinced him to become a Tok’ra host under the guise that a minor Goa’uld had come to her to offer his services to her. He had accepted the offer mainly due to his friend Samantha’s experience with her symbiote, Jolinar.
Apparently Lantash and Jolinar had been in a relationship spanning over 600 years. Oddly enough it hadn’t been becoming a host that weirded him out the most; it was suddenly being in a long-term relationship with two symbiotes and a fellow slave who had been his friend for years. Sam had only laughed and told him he would quickly get used to it, and that he would soon realize that there were many benefits to being blended.
Having instant access to Lantash’s genetic memory had proven to be a major bonus, and had helped him put many things into a better focus. It had also given him a much better understanding of many Goa’uld dialects, which had been useful in his quest to translating the old texts for their queen.
4) In another reality Daniel fell on very hard times after his “revelation” and was unable to even get a job teaching foreigners English. His obsession with his findings were such that he was unable to keep a regular steady job and soon found himself with no job, no income, no apartment, no colleagues who would take him seriously, or even talk to him at all.
This time around Dr. Langford didn’t find the Chappa’ai in 1928 on the Giza Plateau, or anywhere else in Egypt, and therefore his daughter couldn’t recruit Dr. Jackson after his disastrous speech.
He slowly drove himself insane and eventually ended up at the same asylum as his grandfather, where he lived out the remainder of his days trying to convince anyone who came within ten feet of him that aliens really did use the Egyptian pyramids as landing platforms.
5) The Abydonians had been forgotten by Ra several centuries before and, while not really that advanced, they were well-connected and respected traders among the planets with little or no influence from the Goa’uld. They didn’t tell the Tau’ri this though, but Daniel still ended up married to Sha’re and Kasuf insisted that Daniel had to take his new wife with him to his homeworld. In exchange their peoples would become allies and he, Kasuf, would introduce Earth to some of their allies.
Sha’re taught him their particular dialect of Ancient Egyptian and how to read their written language. Like her Dan’yel she had a gift for languages and they would spend any time they could teaching each other what they knew, and applying it to what was currently happening.
Kasuf kept his promise and introduced SG1 to many of their allies, including the Tollan whom they were trading Naquadah with.
The Tollan were researching an old myth about an ancient, highly advanced city that was supposedly hidden somewhere underwater. As this sounded remarkably like the Earth myth about the Lost City of Atlantis they proposed a collaboration in order to research this particular myth from several points of view in an effort to find something to overpower the Goa’uld with.
Over the years several other worlds joined in on the project, as variations of the Atlantean myth appeared on about a dozen other planets. Not all of them believed in it, or were willing to take part in something that might lead to open rebellion against the System Lords, but some did in exchange for being allowed to be a part of the expedition if they found the city.
When Daniel and Sha’re finally found the address, and the eight symbol proved that Atlantis was in the Pegasus Galaxy, it wasn’t just an expedition from Earth that left to explore a new galaxy. It was representatives from Earth, Abydos, the Tollan, and four other worlds. And Daniel and Sha’re were among them.