This sounds like a very fun project. I also run a small local news organization and we use a company that specialize in managing small news sites (Our-Hometown.com, in case you want to give them a look). We’ve been very happy with their service for the past 25 years, so I don’t plan on leaving them any time soon, but, as a self-hoster, I’ve also spent a lot of time thinking about how I’d put together the infrastructure. I think my preference is Nginx plus Varnish for caching. Also, in case you’re not aware of it, Automattic makes a plugin for newsrooms that adds some industry-specific features (github.com/Automattic/newspack-plugin) that looks interesting, though I haven’t tried it.

Lee Hutchinson at ArsTechnica wrote an interesting series about hosting a weather news site in Houston that I thought was awful interesting and might be worth a read. Here’s part 1 and part 2.