According to Google Introduction to Structured Data either schema.org or JSON-LD markup should be enough for Google to pickup structuted data on your website / article. I used them both. In my experince Google was able to pickup breadcrubs within JSON-LD faster while star rating with schema.org was easily to implement.
Because most of the code is not visible to visitors and it's ok you you split your breadcrumbs and star rating into different instances on the page I encourage you to set the rating data over the h1 tag. It's better if you use div itemprop="name" and it's bad if you will create 2 isntances of h1 tag just to fit my example.
- h1 stands for your h1 tag
- "ratingValue" determines the final rating of your article
- "bestRating" determines the best score for your article
- "ratingCount" determines the amount of people who rated your article
<div itemprop="aggregateRating" itemscope itemtype="http://schema.org/AggregateRating">
<div itemprop="name"><h1></h1></div>
<meta itemprop="ratingValue" content="" />
<meta itemprop="bestRating" content="" />
<meta itemprop="ratingCount" content="" />
<div itemprop="itemReviewed" itemscope itemtype="http://schema.org/CreativeWork"></div>
</div>If you want a stanalone rich data generator for your article you can use either this Schema Markup Generator (JSON-LD) or this Schema.org JSON-LD Generator.
When I was learning how to implement rich snippets for my websites I spent some time with them both just to figure this thing out.
Use Google Structured Data Testing Tool to test your code.