2975 - Tinya Wazzo is born on Bgztl, the planet that had been displaced into the Phantom Zone by the Kryptonians by the Eradicator.
2988 - 13-year-old Tinya begins to exhibit her natural power to phase from the Phantom Zone into the matter universe.
2994 - 19-year-old Tinya is injured during he Legion of Super-Heroes battle with the White Triangle Daxamites, losing her ability to phase. She is presumed dead.
2995 - 20-year-old Tinya's planet Bgztl is found in the Phantom Zone by Querl Dox during his experiments with Connor Kent. She is able to appear in the matter universe, but not take full material form.
2998 - 23-year-old Tinya rediscovers her ability to take a material form, allowing her to reconnect with Jo Nah. She begins studying hand-to-hand combat with Val Armorr.
3000 - 25-year-old Tinya is heartbroken when Jo-Nah is lost. She is comforted by Brin Londo, and becomes pregnant with his child. The stress of childbirth costs her her ability to phase. Her child is raised by Brin & Jo-Nah.
3004 - 29-year-old Tinya begins forcing her powers to manifest again, appearing to Jo Nah & Brin Londo.
3005 - 30-year-old Tinya is contacted by Querl Dox when the Legion of Super-Heroes reforms, who manages to restructure her powers, returning her to Jo Nah and Brin Londo.
Phantom Girl (or Apparition) is one of the classic Legion members. She originally debuted in a story called 'Supergirl's Three Super Girl-Friends', so she's always had a vague "children's version of sex in the city" vibe to her. She's free to have slightly more complex relationships because she's not the CENTRAL female character.
Also, she has some very straightforward powers that seem to have really inspired some of the writers over the years to come up with some very clever explanations for. Like most of the Legion, she originally simply had the ability to become intangible because EVERYONE on her planet (Bgztl?) could. Somewhere along the way, however, the notion came about that the reason she could do that was not because ALL her people could become intangible, but because her entire planet was actually in a different dimention. What was actually happening was that she had the ability to phase INTO our reality. That's actually a fantastically cool idea. Because the Legion was crafted as Superboy supporting characters, it wasn't long until someone came up with the idea that her planet was actually phasing from somewhere within or adjacent to the Phantom Zone, which has some very cool synergy to it.
Also, we should probably talk about her costume. Her original outfit with the big P on it isn't really remembered as well as her history of wearing what is essentially 70's jumpsuits with holes cut out. She really was played for sex appeal for a long time, but the costume that came together in more recent versions of the character actually works pretty well. Still, I kind of like the original version just for her to wear when she first joins.
We've made a few minor changes, but for the most part it feels more like we're taking what is already in place and just extending it to it's natural conclusion. We've introduced the idea that a massive teleportaiton disaster in Krypton's past was the reason they became isolationist. Since the Phantom Zone is actually a kryptonian discovery, it makes a pretty clear sort of sense that Tinya's home planet of Bgztl was actually phased into the Phantom Zone BY that accident. This is more than a thousand years later, after all... it sort of works that her planet has spend all that time adjusting to it's new circumstances.
Also... There was an in-continuity love triangle between Tinya, her long-time love interest Ultra Boy, and Timberwolf, who had an affair with her while Ultra Boy was lost in another galaxy. There was a child involved... but this plotline happened when the long-running Legion Timeline was starting to be picked apart before they started having tons of continuity reboots. We decided to include it, but have it play out in a very deliberate way: If Phantom Girl had her child but was then seperated from it, we liked the idea of Ultra Boy and Timberwolf choosing to put aside their difference so they can raise their mutual lover's child together. Even better, when she DOES return to them... rather than playing up the love triangle, isn't it more interesting to make them a polyamorous family? it's the year 3000, after all... and what a fun way to have these classic characters grow and evolve!