Within the scope of the self-consistent-field (SCF) and mean-SCF (MSCF) approximations, static-concentration-waves and Matsubara—Kanzaki—Krivoglaz lattice statics methods, on the basis of state-of-the-art diffraction data concerning coherent and diffuse scattering of radiations in (dis)ordered f.c.c.-Ni— Fe alloys for various composition—temperature regions, and on the basis of data of independent magnetic measurements, the regular parameterization and estimation of ‘pair-wise’ interatomic interactions of the various nature (namely, ‘direct’ short-range ‘electrochemical’ and magnetic contributions as well as indirect long-range ‘strain-induced’ interaction) have been carried out taking into account their concentration and temperature dependences. As shown unfortunately, many of available ‘electrochemical’ interaction parameters obtained with use of the well-known ab initio and semi-phenomenological computational methodologies are limited in their applications for the statisticalthermodynamic analysis of f.c.c.-Ni—Fe alloys because most of them are contrary to the regularities of a ‘mixing’-energy symmetry and, as a result, to the symmetries of observed L1$_{2}$-Ni$_{3}$Fe-, L1$_{0}$-NiFe or L1$_{2}$-Fe$_{3}$Ni-type ordered phases. The ‘strain-induced’ interaction energy is anisotropic, long-range and quasi-oscillating function of a distance between the solute atoms in a host crystal (throughout the temperature—concentration region of f.c.c.-Ni—Fe alloys). Combined ‘paramagnetic’ contribution to the ‘mixing’ energy depends implicitly and essentially on concentration of Fe atoms, and its minimum Fourier-component values fall in the range of Invar compositions of Ni—Fe alloy. The temperature dependence of total ‘mixing’ energy is mainly due to the significant temperature-dependent magnetic contribution to it, and there is no need to take into account the effects of both substitutional correlations between atoms and many-particle interatomic-force interactions for characterization of microstructures developed by atomic ordering and (or) solid-phase precipitation in f.c.c.-Ni—Fe alloys. As expected, within the scope of the MSCF approximation, the estimated energy parameters of ‘exchange’ interactions in 1st coordination shell, $J_{NiNi}(r_{I})$ and $J_{NiFe}(r_{I})$, correspond to the ferromagnetic interaction between magnetic moments in Ni—Ni and Ni—Fe atomic pairs, and $J_{FeFe}(r_{I})$ corresponds to the antiferromagnetic interaction between magnetic moments in Fe—Fe atomic pairs.