Depends a bit on how fancy your Hugo-site is. Unless you’re just feeding markdown into a pre-made template, you’ll at least use the Go template syntax, since that’s what Hugo’s templates are written in.

And if you want to integrate Hugo with anything, Go is the way.

Depends a lot on your set-up. Many pair Hugo with a headless CMS for exactly this reason.

Even with a standard Hugo set-up, most content is in Markdown files, so one could also just train someone from marketing on how to edit those. Not exactly rocket science.