I think it might be, there’s no way Anakin would be able to buy proprietary hardware or software. So either he stole it, which his mother probably would not have allowed. Or he was able to scrap all the parts together because there is a template for humanoid protocol droids that we have also seen round Star Wars. And then the software itself either Anakin programed entirely himself, (which I know he’s very smart, but even that seems a stretch) or he forked it. So it would make more sense that there was an open source catalog of protocol droid software. It also would make more sense due to the fact that a lot of people have droids, but they are not all created equal. I would think many of the droids on Coruscant were proprietary, while many of the droids in the outer rim are open source.
Yup, protocol droids needed to be bipedal to integrate better with the average lifeform. Astromechs were tools that were exposed to atmosphere and vacuum. I do find it a little strange that canon chose to make the astromechs only communicate with beeps and boops that skinbags needed to learn the language of instead of just having them do speech synth.
Canon typically is written after scripts are to fill in back story, his beeps and blips were entirely made because George Lucas was/is a technical guy and made his career out of incorporating new fx techniques