When I taught preschool kids Bible class I just made a felt rock with couple of lines on it & couple of layers glued together & made a slingshot out of Y of a small tree branch & put the "rock" in the rubberband I had attached & pretended to hit Goliath in head & I knocked him down. I did not let kids play with rubberband slingshot! I had both figures of David & Goliath & background of outdoor mountain & valley area. All my figures were felt, they used to have them & you cut them out & assembled them plus I add what I needed to get the story so they could understand it. If story was about Peter by the sea & there was "no sea" I made a felt sea so I could tell more stories using some of same pages for different stories by changing part of background & different figures. Sounds like your Goliath is a doll. Hope this helps!

I know this is old not sure if you found your answer but what about using a brass fastener to attach his feet then he would rotate on it and lay down

Here is a link that might be useful: brass fastener