I wanted to follow up and thank you all for your input.

This afternoon I put a large pan of water on the stove and heated the water up to about 180 degrees. It took less thank 15 seconds per assembly to free up the wrist pins in the pistons.

Dried them, sprayed them with a rust preventative, moved the rod and wrist pin around repeatedly in all directions and they've been sitting now for several hours. Keep trying them and they move as good as new.

Really appreciate your help!