For the time being, I am no longer working on the iPhone app. If it isn't functioning as you'd like, I'd suggest trying my online ear trainer. It is my best ear training tool, and the only one I am supporting at the moment.

Have you confirmed that your iPhone isn't in Silent Mode? When in Silent Mode, you won't hear any sound from the online ear trainer. Obviously, you'll want to check that your volume is turned up as well.

No. The online app is tightly integrated with account logins for saving settings and custom scripts. As such, it currently requires an internet connection and cannot be downloaded for offline use.