Minimal parallelism was recently introduced [3] as a way of using the rules of a P system: from each set of applicable rules associated to a membrane, at least one rule must be applied. In this paper, we consider the minimal parallelism for P systems with active membranes without polarizations, using additional features, such as separation operations, changing membrane labels, catalytic or cooperative rules, etc. With several combinations of such features we obtain computational completeness. In cases where membrane division (of elementary or non-elementary membranes) is allowed, we show how SAT can be solved in polynomial time.