Is there a way to enable sync and disable edit mode on feature services using the Python API?
Take a look at the Updating Feature Layer Properties Guide. Use a FeatureLayerCollection object to load the feature service, then use the manager property to access the FeatureLayerCollectionManager. Create a new dictionary with appropriate values for capabilities and syncEnabled, and use that with the update_definition method and you should be on your way.
Exactly what I was looking for, thanks!
Although I couldn't get it to disable the allowAppend parameter...