Tangential Related: how do people use static site generators (SSG) when they have more than 1 team member who's publishing site updates? Are they having the SSG trigger off of a git push?
Zola has instructions for how to set up git -> site update automation to Netlify or Vercel through GitHub or GitLab. I setup that process to try that out on both for a website for a local org I volunteer for and it was quick to get going. Not sure how easy a non-technical user might find updates though.
Many people will have a Github Pages or GitLab Pages setup where their static website is hosted by Github or GitLab and generated by their respective continuous integration tools to automagically update the website upon pushing to the repository.
Yup, on a merge into a release branch. Netlify makes that workflow a breeze to set up. Zola also has pretty easy integration with netlify.
Yup, most SSGs have pretty good support for GitHub actions or other CI tools.
Do you mean in the case of near-simultaneous commits? Continuous Integration (CI) can be setup to build each commit or abandon a build if a newer commit comes in, and then the deploy step would use the latest build available.