Adbert Alzolay is the only of the four that gets me excited. He's in AAA right now and is 2-1 with a 2.12 ERA. I wouldn't be surprised to see him at Wrigley some time this season.
Oscar De La Cruz is not off to a good start this year. He is in AA Tennessee and is 2-3 with a bloated ERA of 7.48.
Tom Hatch is also in AA but is doing pretty well, posting a record of 3-1 with an ERA of 3.07.
Alex Lange is in High A ball with the Myrtle Beach Pelicans. Both he and Hatch are in just their second year of pro ball, so they've got a long way to go.
There are also Chrome versions of each of the four prospects: