Ask HN: Hackable Smartwatch for Kids?

Does anybody know of open source/open hardware smartwatches for kids that are hackable (in the maker sense, not in the black hat sense), or efforts to root/hack/install custom firmwarm/OS on existing off-the-shelf kids' smartwatches?

Some criteria I'm looking for:

- Camera, microphone, and display for placing video call

- WiFi (802.11n at 2.4 GHz is enough, no need for 802.11ac/5 Ghz)

- 4G LTE (i.e. it needs to have a built-in nano-SIM slot)

- GPS and GLONASS

- Water resistance (no need for diver's rating, IP67 is probably enough)