It looks like Pi-hole might not be listening on the correct interfaces. Check to make sure that you configured Pi-hole to use the IP of the interface which the other devices can reach it on (run pihole -r to reconfigure this). So long as your network IPs are not accessible by the internet directly, it shouldn't matter much whether you hide them or not. It could help debugging. Or, you could disclose them privately: How do I debug my Pi-hole installation?