I'm not super active in the humanoid robot space anymore, however I did my PhD about 9 years ago in HRI. That was the time of Boston Dynamics, DARPA robotics challenge, and Aldebaran's Pepper and Nao robots.
You mentioned you are building everything open source. What happened with ROS and related projects? Do you build on top of that, or is that all super outdated that a reboot was needed?
Another question I have is: why are you choosing a two-legged human over a four-legged one?
My experiments with two legged robots were mostly bad. Not only did they fall basically all the time but they also had a big drift. So far, I have not seen any large improvements. But again, I might be very outdated.
I always said to my colleagues. The main point stopping robots from picking up is a stable platform. And with the platform I mean walking.