Elehayym Van Houten
Elly was born in Solaris to Erich and Medena Van Houten eighteen years before the game. They were members of the First Class Gazel; her father was a high-ranking military official, and her mother was his dutiful wife. Elly was an only child, and thanks to this nice arrangement here, she had a very well-rounded life. ^.^ However, I think she looked up to her father a lot, and sought his approval; it's for this reason that she entered Jugend when she was younger, despite the fact that she was often targeted and taunted about her looks by the other students. General sentiment was that she was actually a Lamb (surface dweller), and Elly also suspects that this might be true... When she was a child her father secretly employed a Third-class woman as her nanny, and in the back of her mind, she thinks this woman is her real mother.
Birthplace: Etrenank, Solaris
Height: 164cm (5'6")
Weight: 46kg (101 lbs.)
Clothing size: medium
Shoe size: 23.5cm
Ring size: 9
Gear: Vierge, Regulus
Despite all of that, Elly's life ran smoothly, and I think we can assume that she was a good student at Jugend - especially with Kelvena as a roommate. ^.^ She has the potential to be an Element, though she works only in Gebler's forces instead (though I think she was regarded as as student with no potential for the longest time). But at age seventeen - one year before the game - Elly was cornered by her superiors and forced to take an enhancement drug called Drive. Unfortunately, she didn't react very well to this drug; although it did release her potential, it also caused her to kill and injure several people when she lost control of her ether. Her potential was rated at over 400 - off the charts, in other words - and she was relegated to her command in Gebler, after confinement for her "crime."
Mere hours before the game started, Elly was sent on a covert mission to Kislev, with instructions to relieve them of a new model gear in their hangars; Kislev didn't feel like rolling over however, and gave chase, causing Elly and her team to make an emergency landing in the remote town of Lahan. This event is the catalyst that began the trials of the game for both Elly, Fei, and the friends they would meet later in the story.
The rest can be seen by playing Xenogears. ^.^ You can check Miang's profile for more in depth information on the connection between the two.
Sophia (originally 'Elehayym') was born as the middle child to Ashera, the original leader of the religion that later became known as the 'Nisan Sect', also a child known for her ether power. She fell ill while she was still quite young, and she was sent to a monestary to recover, where she met Lacan for the first time and became his friend. Penel became her teacher at this monestary, but when she was 13, he was attacked and killed, and Krelian took Sophia away from the monestary and into his care. The Nisan sect split from Nimrod and years later (when Sophia was 20), she returned to lead the religion with the aid of Krelian and Lacan.
Sophia is famous for leading the masses in the war against Solaris. Nisan amassed alliances and armies that the world likely hadn't seen for a very long time, and waged war against their oppressors... but unfortunately, her role as the "Mother of Nisan" prevented her from having a normal life. She was in love with Lacan, but never really had the chance to express herself, except near the end. At age 25, Sophia commandeered Shevat's flagship - Excalibur - and crashed it into Solaris's flagship to free her forces from an ambush, and died in the crash. Her maryrdom drove both Lacan and Krelian over the edge, but it ended the war... and to this day, her portrait still sits in the topmost room of the Nisan cathedral. ^.^
Four thousand years before the game, another of Elly's incarnations was born in the country of Zeboim, during the era of technology. She made her career as a nurse, and met Kim when she was 28. ^.^ I've no idea if they were actually married or not, but they had a life together, and one of the sources of strife between the two was Elly's infertility (caused by radiation poisoning), which Kim "fixed" by created Emeralda. Before the girl could really be awakened, though, the laboratory was attacked, and Elly sacrificed her life to keep them from reaching Kim.
Elly (Year 0000)
Even with wonderful historical records like the Perfect Works, there's not much to say about Elly's first incarnation after the crash of the Eldridge. She and Miang were born from the body of Original Elly (the construct created by Zohar), and once separated, she eventually made contact with Abel and fell in love with him. This was all in line with her role as the Contact's protector - something that is reflected in every other incarnation as well - but that was put to a stop when Cain and his descendants struck them down for rebelling against his rulership. Elly sacrificed herself to save Abel's life, though whether he ended up dying despite that is unknown.