  We compute the mass, radius and tidal deformability of stars containing phase
transitions from hadronic to quark phase(s). These quantities are computed for
three types of hadronic envelopes: purely nuclear, hyperonic, and
$\Delta$-resonance--hyperon admixed matter. We consider either a single
first-order phase transition to a quark phase with a maximally stiff equation
of state (EOS) or two sequential first-order phase transitions mimicking a
transition from hadronic to a quark matter phase followed by a second phase
transition to another quark phase. We explore the parameter space which
produces low-mass twin and triplet configurations where equal-mass stars have
substantially different radii and tidal deformabilities. We demonstrate that
while for purely hadronic stiff EOS the obtained maximum mass is inconsistent
with the upper limit on this quantity placed by GW170817, the inclusion of the
hyperonic and $\Delta$-resonance degrees of freedom, as well as the
deconfinement phase transition at sufficiently low density, produces a
configuration of stars consistent with this limit. The obtained hybrid star
configurations are in the mass range relevant for the interpretation of the
GW170817 event. We compare our results for the tidal deformability with the
limits inferred from GW170817 showing that the onset of non-nucleonic phases,
such as $\Delta$-resonance--hyperon admixed phase and/or the quark phase(s),
are favored by this data if the nuclear EOS is stiff. Also, we show that
low-mass twins and especially triplets proliferate the number of combinations
of possible types of stars that can undergo a merger event, the maximal number
being six in the case of triplets. The prospects for uncovering the first-order
phase transition(s) to and in quark matter via measurements of tidal
deformabilities in merger events are discussed.
