In this study, the effects of reinforcing the Elium®—an acrylic-based thermoplastic resin known for its high strength, and recyclability—with polyacrylonitrile (PAN) nanofibers on its mechanical, thermal, and shape memory effect (SME) were investigated. A novel aspect of this work is the dual doping of polyacrylonitrile (PAN) nanofibers with graphene nanoplatelets (GNPs) and iron (II, III) oxide (Fe3O4) nanoparticles, a combination not previously explored in Elium® composites, to ameliorate structural and SME properties. The GNP-doped composites achieved the highest tensile strength (68.8 MPa) and elongation at break (9.95%), while the hybrid nanocomposites doped with both GNPs and nano-Fe3O4 demonstrated a balanced enhancement in mechanical strength (62.6 MPa) and ductility (9.18%), compared to the pure Elium®, which exhibited a tensile strength of 44.4 MPa and elongation at break of 7.95%. Thermomechanical analysis demonstrated that nanofiber reinforcement improved storage modulus by 34.5% (from 2925 to 3935 MPa) and increased the glass transition temperature (Tg) from 81.4 to 90.8 °C in the hybrid composite. SME evaluation revealed recovery rates of 95% for GNP-doped nanocomposites, 86% for Fe3O4-doped nanocomposites, and 90% for hybrid nanocomposites, confirming the synergistic effects of dual doping. These findings demonstrate the potential of PAN/Elium® nanocomposites for advanced engineering applications.