Which German capital ships could join an early war?

Could Bismarck be completed quickly enough to enter this early war?

Probably not; the Scharnhorst-class ships are much more plausible participants if Germany intervenes.

Bismarck would probably not be finished soon enough for the early fighting. The Scharnhorst-class ships are the more plausible German capital ships if Berlin chooses to intervene. Germany had less scope to compress Bismarck's schedule than Britain had to accelerate some of its own construction because British industry was larger and was not yet under air attack. A declared war cannot instantly convert an incomplete hull into an operational battleship. Any German role must therefore be built around forces actually near readiness at the scenario's start.