The complex magnetic structures, spin-reorientation and correlated exchange interactions have been investigate in Er0.5Dy0.5FeO3 using bulk magnetization, neutron diffraction, specific heat measurements and density functional theory calculations. The Fe spins order as G-type antiferromagnet structure depicted by Γ4(Gx,Ay,Fz) irreducible representation below 700 K, similar to its end compounds. The bulk magnetization data indicate occurrence of the spin-reorientation and rare-earth magnetic ordering below ∼75 K and 10 K, respectively. The neutron diffraction studies confirm an “incomplete” Γ4→ Γ2(Fx,Cy,Gz) spin-reorientation initiated ≤75 K. Although, the relative volume fraction of the two magnetic structures varies with decreasing temperature, both co-exist even at 1.5 K. At 8 K, Er/Dy moments order as cy arrangement develop, which gradually increases in intensity with decreasing temperature. At 2 K, magnetic structure associated with cz arrangement of Er/Dy moments also appears. At 1.5 K the magnetic structure of Fe spins is represented by a combination of Γ2+Γ4+Γ1, while the rare earth moments coexists as c R y and c R z corresponding to Γ2 and Γ1 representation, respectively. The observed Schottky anomaly at 2.5 K suggests that the “rare-earth ordering” is induced by polarization due to Fe spins. The Er-Fe and Er-Dy exchange interactions, obtained from first principle calculations, primarily cause the complicated spin-reorientation and cy rare-earth ordering, respectively, while the dipolar interactions between rare-earth moments, result in the cz type rare-earth ordering at 2 K. PACS numbers: 75.25.-j, 75.47.Lx, 75.30.Gw, 71.20.-b