I have spent quite a lot time with the same quest but did not get anything which I can say was good.
Coming to your points
There are no examples which I can say was comparable with Java of .Net PageFactory, I find this blog post interesting. For PageObject refer here. Apart from there, regular code reviews and strict coding style was the only thing I found very helpful if you are working with people who do not have good exposer with dynamic languages.
A very short stack overflow discussion here which I sometimes use when I really want to say “No”.
2.For multithreading, you can refer here you can also use jPython as it uses JVM and with all the pros(and may be cons) of Java threads.
Not sure if this is what you need but check out Robot Framework at robotframework.org/. Documentation seems decent enough. Haven’t used it yet but I’ve been hearing a lot about it lately.
Good luck