Lundgren just finished pitching for Australia in the WBC. He's young, yes, but appears to be an extreme control pitcher without much of a way to miss bats. 2006 will be his first stint in AA.
Alvarado hasn't played for the Mets. In 2005 he was in the independent Northern League after spending time in the Pittsburgh (most of his career), Milwaukee, and Detroit organizations.
Villalon last has stats for 2003, when he made 13 starts for Tennessee (St. Louis AA). He's a Cuban defector who was originally signed by Tampa Bay in 2000. He'll join fellow Cuban defector Arian Cruz.
Colina spent 2004 in St. Louis after six years in the Colorado organization. Allegedly he won some sort of MVP award playing in one of the Latin American leagues in 2005.
Baseball America listed that Schramek was released, so I have no idea. He still needs to be converted to a pitcher.