Using deep color magnitude diagrams from HST ACS imaging, we have derived detailed star formation and chemical enrichment histories of a representative sample of six M31 dwarf spheroidal (dSph) companions in order to compare directly the timing, duration, and strength of their first episodes of star formation to those of Milky Way dSph satellites. We derive robust and homogeneous distances to the six galaxies using different methods based on the properties of the RR Lyrae stars. Our observations yield a time resolution at the oldest ages of ~1 Gyr, allowing meaningful comparisons to the MW satellites. The six dSphs present a variety of star formation histories (SFHs) that are not strictly correlated with luminosity or present distance from M31 (e.g., a significant range in quenching times from 9 to 6 Gyr ago). In agreement with observations of MW companions of similar mass, there is no evidence of complete quenching of star formation by the cosmic UV background responsible for reionization, but the possibility of a degree of quenching at reionization cannot be ruled out. We do not find significant differences between the SFHs of the members and non-members of the vast, thin plane of satellites. The SFHs of the ISLAndS M31 dSphs appear to be more uniform than those of the MW dSphs. Specifically, the primary difference between the SFHs of the ISLAndS dSphs and MW dSph companions of similar luminosities and host distances is the absence of late-quenching dSphs in the ISLAndS sample. These conclusions appear to be confirmed and strengthened by shallower observations of a more complete sample (Weisz et al. 2019). Fundamentally, we are testing the assumption that the early evolution of the Milky Way satellites was typical and therefore representative of dSphs in general.