>Is there a free program I could use to make technical drawings?
Fusion360 is a great tool, and Autodesk has a program available for amateurs:
A) I don't trust Autodesk very much, and B) it's strictly cloud-based. So if they deplatform you or you lose internet, you're basically hosed from any further work on your project. But all-in-all it's a remarkably good product for engineering work like this, and directly supports 3D printing software.
Another possibility is SolidWorks, and they are offering a special deal to EAA members. Both are cheap.
Finally, ofc there's always Blender. And today, that's a very good choice indeed, given the improvements in version 2.8 of the project.
We actually have a thread on this specific topic Anon, the catalog is always your friend here.
Yep everything else has to work as well. I'd recommend really digging in and getting your legs idea going first though Anon. Not only will you learn valuable lessons in the process (and help us all out here as well), but it will serve as a good 'base' after a fashion for you to build up the rest of the project. Just do it!
>Are there any simple solutions for those?
In a word: no. We're pioneering inexpensive, simple approaches here on /robowaifu/ as we go, Anon.
>Is it even realistic at this point to have her make facial expressions?
It is, but it's either rather sophisticated ie, expensive
such as the theme-park animatronics system Disney devised for the Avatar ride, or tends to be kludgey, such as various amateur efforts we've seen thus far (and I'm not judging them, this stuff is very hard to get right tbh). A middle-ground between the two needs to be pioneered here, actually.