Not a biggie, but I would suggest not hard-coding these concrete `Props` in-line - more work to set up test code.  I would suggest a trait `ClientHandlerProps` something like:

```scala
trait ClientHandlerProps {
  def jsonHandlerProps:Props
  def overviewHandlerProps:Props
  def actorsHandlerProps:Props
  def actorHandlerProps:Props
  def playRequestsHandlerProps:Props
  def playRequestHandlerProps:Props
  def deviationsHandlerProps:Props
  def deviationHandlerProps:Props
  def lifecycleHandlerProps:Props
}
```

And then pass an instance in as a constructor argument to this actor.