When you try to install the networkaudioxxx.deb under Jessie, you’ll see which dependencies/versions fail (gcc6 and one other, if I remember correctly).
After updating the entries to stretch and running apt update, install these packages manually:
apt install package1 package2
That way, only these packages are updated and not your entire system. When finished, restore the entries to jessie.
And yes – they will continue to work – at least they did on my Cubox. Of course, YMMV. Godspeed! 