Are there any calf muscles used in foot flexion?

Yes: The main calf muscles are the gastrocnemius and soleus muscles that flex the foot down (point the toes). Lesser muscles involved include the peroneal muscles, the posterior tibial, flexor digitorum longus and the flexor hallucis longus muscle.

Yes: When plantarflexing the foot you are using both your gastrocnemius and soleus muscles in your calf.