Single-phase multiferroic Ba(Fe0.67Ce0.33)(0.01)Ti0.99O3 (BFTO:Ce) and Ba(Fe0.67La0.33)(0.01)Ti0.99O3 (BFTO:La) nanostructures were synthesized by a hydrothermal method (180 degrees C/48h). Rietveld refinement of X-ray diffraction could confirm crystalline phase and lattice deformation by Ce, La into BFTO. The Ce and La doping induce nanoaggregation-type BFTO nanostructural product due to their ionic size effect and chemical behavior with OH- ions. Raman active modes show tetragonal phase and defects due to vacancies in the BFTO lattice. Photoluminescence spectrum involves multiple visible emissions due to defects/vacancies. The observed ferroelectric polarization is enhanced due to shape/size effect of nanoparticles, lattice distortion, and filling of d orbital in the perovskite BaTiO3. The room-temperature magnetic behavior is described due to antiferromagnetic interactions that strengthen by Ce and La doping. The zero-field cooling and field cooling magnetic measurement at 500Oe indicates antiferromagnetic to ferromagnetic transition. Dynamic magnetoelectric coupling was investigated, and maximum longitudinal magnetoelectric coefficient is 62.65 and 49.79mV/cmOe, respectively, measured for BFTO:Ce and BFTO:La. The magnetocapacitance measurements induce negative values that described in terms of magnetoresistance and magnetic phase transition effects. The influence of oxygen vacancy on multiferroicity is evaluated by valance states of O ions.