That seems to sum it up. Looking at the original title to the post, "Calf Muscles - is it worth working on them?" what can we say now?
What we know so far:
The Gastroc. (calf muscle) in an open kinetic chain serves to primarily plantar flex the foot and secondly assist in knee flexion. However, in a closed kinetic chain movement (such as cycling) the Gastroc. will actually help in knee extension (during the downstroke). So during the downstroke, yes, it will contract (whether it be isometrically or concentrically) to stabilize the ankle (along with the tibialis anterior and smaller musculature of the lower leg both anteriorly and posteriorly) or to help in those riders who practice "ankling."
In the upstroke, it will not really assist in that actual upward motion because pedaling is a closed kinetic chain movement, but it can help in this movement. Because we are looking to stabilize the ankle as well, and not allow it to plantar flex as we move the rear foot upward, the Gastroc. will be somewhat involved again for a stabilization-type of role.
This musculature is actively involved in some or all parts of the pedal stroke. It serves to stabilize and/or plantar flex - whatever it may be that the cyclist decides to do, and exactly how this cyclist pedals does not matter right now.
Joint stability is important for many sports. A stable joint is a strong joint, so yes, stabilizing the ankle is probably fairly important during the upstroke and downstroke. How much do we have to train this muscle outside of simply pedaling our bike has yet to be determined.
What I conclude from this is that in untrained or less-trained cyclists who may have poor form or low stability of the ankle joint, stabilization training off the bike may be of benefit. In well-trained cyclists who have a pretty efficient pedaling style, training the actual calf musculature would not seem to provide any additional benefits in power production or efficiency.
Any other ideas or thoughts?