The connectivity you want in a single unit would be nice, but at present it would not be cheap to implement. You are starting to see some of this is AV receivers as they implement Airplay, for example. The manufacturers can do it in those devices at a reasonable price because of the volume of sales. Putting all that into a low volume stereo integrated would be costly at present. Have you looked into a AV receiver with Airplay, although it might not satisfy your stereo needs for music.
There are devices like the Classe CP 800 which is a high quality pre-amp with both USB and digital inputs. It is not wireless however, and it is at a different price point.
I am not an expert, but I think the Apple Airport Express would do a lot of what you you are looking for. It is a WiFI device that also can connect to a analog input on your stereo, although the DAC in it is obviously low end. It also has an optical output to go to a DAC. With Airplay you family can use their various Apple devices with Airplay and direct their music to your rig. If they are familiar with their Apples software, like iTunes and understand wireless a little, they should be able to use the big stereo pretty easily.
Maybe someone with more Airport Express experience can provide you more information.
You could also get a universal remote with macros if you want them to just push a button to get the stereo settings right. You do mention a toggle switch. You cannot do that with a universal, but hopefully they would be willing to do 1 switch manually.
There are devices like the Classe CP 800 which is a high quality pre-amp with both USB and digital inputs. It is not wireless however, and it is at a different price point.
I am not an expert, but I think the Apple Airport Express would do a lot of what you you are looking for. It is a WiFI device that also can connect to a analog input on your stereo, although the DAC in it is obviously low end. It also has an optical output to go to a DAC. With Airplay you family can use their various Apple devices with Airplay and direct their music to your rig. If they are familiar with their Apples software, like iTunes and understand wireless a little, they should be able to use the big stereo pretty easily.
Maybe someone with more Airport Express experience can provide you more information.
You could also get a universal remote with macros if you want them to just push a button to get the stereo settings right. You do mention a toggle switch. You cannot do that with a universal, but hopefully they would be willing to do 1 switch manually.