I'm no attorney, but I'm pretty sure if an independent developer wanted to get the rights to the Legaia name then they'd be able to purchase it since the trademark has been considered abandoned.
Whatever happened to the original creators? Are they just off doing their own thing?
They're most likely working on other projects or doing their own thing. Prokion/Contrail got dismantled by Sony. It's sad, too. The first Legaia was a fairly big hit in Japan - it was even re-released on Playstation: The Best, which was Japan's version of our Greatest Hits label. And it sold about 300,000 copies in the USA. That success enabled a sequel, though with the sequel's flop it's obvious why the trademark wasn't restarted. Sony obviously sees that another Legaia game wouldn't make them money. I do wish they'd buy the trademark again just so they could put it on PSN, though.
The director of Legend of Legaia, went on to produce Tales of Rebirth for the PSP in 2008.
He also did some work on Castlevania: Lament of Innocence.