Hi!
Thank you for your messages! Sorry about reply latency.
I'll try to answer all questions you have asked. :)
First, shortly about the device: There is all features I listed before built-in inside of beautiful IP67 classified covers. IP67 means that its dust and water resistant. 30min in 1m depth. Size of the device is ~ 120 x 60 x 18 mm. There will be two-way communication between the device, web server and mobile app. You can configure your device via mobile app.
There is no indication led, but display can be used in this use case. Device has 128 x 64 pixels OLED display, so its possible use limited spot of pixels to act like indication led and it's very energy efficient.
GPS: I can't surely say what will be highest reporting rate but it should be at least that 5Hz. I'll be back with this when we got more exact information.
BT: We have BT LE 4.1 so it is possible that we have some kind of support for audio routing. Same as in the previous answer I'll be back as soon as we have this information for sure.
We will offer open source SDK and APIs and all common interface protocols are supported.
We will communicate the price in couple next weeks.
I'll be back right away when I have some more exact information to share.
Thanks, we are happy to have you to join our journey!
-t