Yes. Here are some options. Others do exist though.

You could add an Airport Express or Apple TV to your home network/AV system to stream content from your PC/Mac/iOS devices to your current AV system. Both the older Airport Express and the AppleTV have minijack output which you could connect to your current AVR via digital optical input. That's one component of my own home AV system. I also a software called Airfoil to send all sorts of content from my various PCs to my AV receiver. Otherwise you would be limited to Airplay only. Of course you would need a pair of outdoor speakers to add to the A/B speaker selection on your Denon for outdoors.

The workaround to not having a *dedicated* smartphone app to control the show would be using some sort of Remote Desktop app such as TeamViewer to control the show/stream from your PC/Mac.

Question: why would you want to send music to your bluray player? You have a receiver to handle that (see my Airport Express suggestion above). There should only be output from the Blu Ray player. Would you mind providing the model number?