Thanks! I was looking at the Pi Zero due to general familiarity with the Pi ecosystem, but BeaglePlay sounds interesting. I will definitely investigate.
One other thing I’m wondering about is what sort of linux distro would be best? It should boot fast and be robust in terms of not easily getting corrupted if it gets powered off without a proper shutdown. I have intentionally made the C++ software not manage any files locally for this reason, so it would only be the OS that could potentially bork itself.