Thank you for posting this! It is really nice for us to hear about good use-cases like this.
I think bt .tn closed down (or similar) about a year ago unfortunately.
To your questions:
I believe that the output from both stderr and stdout is consumed within the Flic app. This is if I recall correctly. If so, no output is available. This could be changed in a future release, but for now it is the case.
To be honest with you, this is largely a business decision rather than a technical requirement. Sure, some features, such as IFTTT, Zapier, Microsoft Flow, need a Flic account in order to work, but in reality the app does not really need a login for most features. What I can say though is that once you are logged in, the app will not rely on our backend in order to work locally (at all). If our backend goes down your app will continue to work fine, unless of course you log out (in which case you would not be able to log back in again). I do understand your concern and if you truly want to have an offline solution with full control, then I recommend that you take a look at our https://github.com/50ButtonsEach/fliclib-linux-hci. Using that you could yourself fully implement Flic into a Raspberry Pi, for example. If you feel really motivated and don't even want to use our SDK, then you can also take a look at the Flic 2 Open Protocol Specification, but maybe that would require a fair bit of work.
This is mostly due to Apple’s App Sandbox . Basically the Flic app can not access any folder on your computer other than exactly /Library/Application Scripts/com.shortcutlabs.FlicMac. The app also does not have write access, only read and execute, which is why you have to manually place the files there.
Anyhow, I think it is cool what you have implemented. However, I will say that if reliability is critical to your use-case, then a purposefully build Raspberry Pi server might be a better way to go. It is more difficult to guarantee uptime on a Mac since it can go to sleep mode, software updates, etc.. I mentioned the fliclib-linux-hci earlier and I don’t think it would be very difficult for you to set that up, judging by the code you have already written :)