is it possible to change a camera outside of the createScene function?
Yes you can. As long as you have reference to scene, you have access to the cameras.
E.g. if you created a camera with name ‘myCamera’ inside createScene:
const camera = new BABYLON.ArcRotateCamera( "myCamera", 1.05, 1.05, 600, new BABYLON.Vector3(0, 0, 0), scene );
You can access the camera and then update the position for example
const camera = scene.getCameraByName(“myCamera”);