Google maps has reviews, photos and a rating of a local restaurant. The owner would like me to show the latest google rating along with recent user reviews (3 stars and higher) and photos people take. Is it possible to get some or all of this information onto the site? It can be something like an iframe or json which I'll use to create a better looking page
That information isn't available directly via a widget or similar.
However you are able to access it via the API.
You can find instructions and examples at https://developers.google.com/my-business/content/review-data