In this work, we present a comparative study of the three of the seesaw models, viz., type II, inverse and linear seesaw models, to investigate about light neutrino masses and mixings, flavour structure, neutrinoless double beta decay (0νββ) and charged lepton flavour violation (cLFV) decay (µ → eγ). We consider the A 4 flavour symmetry, while some other symmetries, like U (1) X , Z 4 and Z 5 are also included to forbid unwanted terms in the Lagrangian. Taking into account the present experimental data for the known light neutrino parameters from recent global fit data, we compute the currently unknown neutrino parameters such as the lightest neutrino mass (m 1 ), CPV phase (Dirac and Majorana), and effective light neutrino mass in the neutrinoless double beta decay, by considering different VEV alignments of the triplet scalar flavon fields. We also elucidate on the octant of atmospheric neutrino mixing angle, θ 23 , in the light of our predicted results.Finally, we present the region of parameter spaces of m 1 , CPV phases, octant of θ 23 and effective mass measurable in of neutrino less double beta decay experiments, that can be tested in future experiments. We observe that the branching ratio of (µ → eγ) can help discriminate the three seesaw models. Further, the favoured Octant of the atmospheric mixing angle θ 23 changes with the VEV alignment of the triplet flavon field -i.e., the internal flavour structure of the neutrinos is reflected in their composition (mixing). We also find some interesting results in context of mass hierarchy-Octant degeneracy with reference to VEV of the triplet flavon field. The constant F determining the scale of flavour symmetry breaking, seesaw scale and coupling constants of the three seesaw models has also been computed, which puts a constraint among them allowed by the present experimental results. Interesting implications on dependence of scale of flavour symmetry breaking in the three seesaw models is also presented in discussion.

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Measurements of disappearance channel of long baseline accelerator-based experiments (like NO[Formula: see text]A) are inflicted with the problem of octant degeneracy. In these experiments, the mass hierarchy (MH) sensitivity depends upon the value of CP-violating phase [Formula: see text]. Moreover, MH of light neutrino masses is still not fixed. Also, the flavor structure of fermions is yet not fully understood. We discuss all these issues in a highly predictive, low-scale inverse seesaw (ISS) model within the framework of [Formula: see text] flavor symmetry. Recent global analysis has shown a preference for normal hierarchy and higher octant of [Formula: see text], and hence we discuss our results with reference to these, and find that the vacuum alignment of [Formula: see text] triplet flavon [Formula: see text] favors these results. Finally, we check if our very precise prediction on [Formula: see text] and the lightest neutrino mass falls within the range of sensitivities of the neutrinoless double beta decay [Formula: see text] experiments. We note that when octant of [Formula: see text] and MH is fixed by more precise measurements of future experiments, then through our results, it would be possible to precisely identify the favorable vacuum alignment corresponding to the [Formula: see text] triplet field as predicted in our model.

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