Congratulations to you and your family! I think
Eva can work quite nicely with a longer middle name, but I'll try a few one-syllable names as well...
Eva TessEva BelleEva FleurEva GwenEva JoyEva LaureEva Plum
Eva CarolineEva ConstanceEva GwendolenEva JessamineEva LorraineEva MarianneEva PenelopeEva RosemaryEva SuzanneEva Tamsin