maybe not but that is a big MAYBE. I would go with snails with fry. The Synodonis will be great with your adult fish.
Just to give you an Idea. My LFS had some cichlid fry that had been born in one of the tanks and when ever I went in I checked on them to see the progress. one day I went there and they were all gone. Only 2 months old still to small to sell I asked where they were. They moved the plant and there was a big fat happy catfish. It had jumped the divider between tanks and ate all the fry in 1 night.
This might also give you and idea Synodonis are very interesting on how they bread in the wild. They will leg eggs in with another mouth brooders eggs. When the mouth brooder pics up the eggs it picks up the synodonis eggs as well. The Synodonis eggs will hatch first and they will feed on the cichlid eggs in the mothers mouth until she spits them out. This is another reason I wouldn't trust them with fry.