Although the book doesn't define their gender, their designs suggest to me that they're male. The female Resistance members, even the soldiers, were always seen wearing either a skirt or a dress.
MMZOCW refers to the two as Elpizo's followers. Other than that, there really isn't much information about them. One can presume that they're deceased, but oddly enough, their bodies aren't visible among the Reploids that died in Operation Righteous Strike.
Fun fact: The names Isos and Pasos were supposed to be assigned to Crea and Prea, but apparently Inti had Nakayama's notes mixed up.