Summary: In Part I (cf. the preceding review) the \(N\)-soliton solution has been constructed for the generic system associated with the \(sl(2,\mathbb{C})\) case of the scheme for the unified descripton of integrable relativistic massive fields. Here, solutions are isolated for reductions of this system, including the (conventional) complex sine-Gordon equation, the massive Thirring model and another complexification of the sine-Gordon equation defined by the Lagrangian \[ L={| \partial_ \mu\varphi |^ 2 \over 1-| \varphi |^ 2}+ | \varphi |^ 2- {J^ 2_ \mu \over 2 | \varphi |^ 2(1-| \varphi |^ 2)}, \] \(J_ \mu=i(\varphi^*\partial_ \mu \varphi-\varphi \partial_ \mu \varphi^*)\). The latter model is shown to exhibit decays and fusion of (subluminal) solitons. The reduction to the conventional complex sine- Gordon appears to be even more interesting as it cannot be defined by simply restricting the linear problem to some real form of \(sl(2,\mathbb{C})\) algebra, and the relevant involution turns out to be quite nontrivial. When the background is flat, this involution degenerates and so the \(N\)- kink solution for the reduction cannot be extracted from the generic \(N\)- kink solution directly. This difficulty is bypassed by seeing the flat background case as a limit of an exponential one.