Context. The James Webb Space Telescope (JWST) enables the identification of quiescent galaxies out to early epochs, offering a transformative view of their evolution. However, the photometric selection of quiescent galaxy candidates (QGCs) and the derivation of their key physical quantities, such as stellar masses (M★) and dust attenuation, remain highly sensitive to the assumed star formation histories (SFHs), where dust─age degeneracies and modelling choices continue to stand as a major source of uncertainty. Aims. We aim to quantify how the inclusion of JWST/MIRI data and different SFH models impacts the selection and characterisation of QGCs. We test the robustness of the physical properties inferred from the spectral energy distribution (SED) fitting, such as M★, age, star formation rate (SFR), and dust attenuation (AV). We study how these parameters impact the quiescence criteria of the galaxies across cosmic time. Methods. We performed SED fittings for ∼13 000 galaxies at z ≤ 6 from the CEERS/MIRI fields with a ≤20 optical to mid-infrared broadband coverage. We implemented three SFH prescriptions: a flexible delayed model, a non-parametric model, and an extended regulator model. For each SFH, we compared the results obtained with and without MIRI photometry and dust emission models. We evaluated the impact of these configurations on both the number of QGCs, selected on the basis of their rest-frame UVJ colours, specific SFR, and main-sequence offset, as well as on their key physical properties, such as M★, AV, and stellar ages. Results. The number of selected QGCs varied significantly, with the SFH ranging from 70 to 100 out of a mass-complete sample of ∼5000 galaxies, depending on the model. This number increased to 103─180 when MIRI data were included, driven by improved constraints on both dust attenuation and M★. We found a strong correlation between AV and M★ of QGCs at z ≤ 2.5, with massive galaxies (M★ ∼ 1011 M⊙) shown to be ∼ 1.5 − 4 times more attenuated than low-mass galaxies (M★ ∼ 109 M⊙). Regardless of the SFH, ∼13% of QGCs exhibit significant attenuation (AV > 0.5) in support of recent JWST results on dust-rich quiescent galaxy candidates.