Even though it's only in multiplayer, you have to think they could've made them SIGNIFICANTLY different from EVE Hypos. Maybe for the logo, a leaf? A slug? A serpent, for the sake of another reference?
P.S.: What IF ADAM Hypos were in the main game? "There's enough ADAM out there for EVERY Plasmid, Tonic, and Health/EVE Upgrade, but you'll have to be quite clever to find it all!"
P.P.S.: Where DO they get EVE? They might make it from ADAM, for yet another reference, but I'm STILL not sure.