We use this. It's much better then bitbucket. We are a distributed team of about 15ish devs. It has had some growing pains, but the support team is top notch and extremely responsive.
I agree with both (1) and (2). We require all devs, as a part of the onboarding process to read, improve and correct the docs for onboarding for each new hire. A PR is required. This forces all developers to understand what happens when something actually breaks and also how to locate the information, should the need arise.
This is also why we've never Dockerized. It masks too many issues and no one seems to have a clear understanding of how all the garments are stitched together.
I would advise to be cautious with cast. It can be powerful and mask bugs if you arent careful (ie, type checker said it's ok, so it must be ok!). You may also want to drop a comment if you use it.