We study conditions of the appearance of U (1) & times; Z2 superconducting states that spontaneously break timereversal symmetry (BTRS) on a square lattice as a function of applied strain. Calculations show that if critical temperatures coincide at zero strain, they exhibit a linear kink and no kink otherwise for uniaxial and isotropic strain. Linear kink is absent for shear strain. We find that in general, the microscopic calculations show a complex phase diagram, for example, nonmonotonic behavior of BTRS transition. Another beyond-Ginzburg-Landau theory result is that U (1) critical temperature can decrease under compressional [100] uniaxial strain for small Poisson ratio materials. In the second part of the paper, we consider the effects of boundaries and finiteness of the c transitions. A finite sample has BTRS boundary states with persistent superconducting currents over a wide range of band filling. Overall, the BTRS dome occupies a larger band-filling-temperature phase space region for a mesoscopic sample with [110] surface compared to an infinite system. Hence, the presence of boundaries helps to stabilize the BTRS phase.