I removed all of the parts specific to holding electronic components, and instead of using screws to hold the whole thing together, I made little cylindrical connectors. You can see those in the "extras" file.
The tallest ones are used to connect the body to the arms/legs. The mid sized ones are used to connect the butt plate to the middle leg. The smaller ones are used to connect the body to the butt plate. These connectors should be pretty tight so they'll probably hold pretty well but some simple glue will make them stick together if it's not staying.
The head will just slide on, and once you turn it, it should fall into a groove so the head can rotate but it shouldn't fall off easily.
Also I have not actually printed this myself, so let me know if there are any issues while you're trying to print and I'll attempt to fix them. But everything should be printable at 0.3mm layer height and all the supports needed are already on the models. Also this model should be scalable to some degree. The pegs make it hard to do so, but you should be fine downsizing it a bit.
I hope you enjoy this model! Post if you make one!