Providing some data in JSON-LD and some data in Microdata should be fine (but if both were about the same entities, you should denote this explicitly). It can become problematic if you want to connect the entities, though.
Connecting WebSite and Organization
Speaking of connecting entities, I would recommend to do this for your WebSite and Organization items. For example, you could state that your Organization is the publisher of the WebSite, and/or that the WebSite is about the Organization.
There are two ways how to achieve this in JSON-LD:
- use one
script element and embed the Organization node as value
- keep both
script elements (or one script element with @graph), give each node a URI (with @id) and reference these URIs as values
The former probably has better consumer support, the latter makes it more suitable to provide multiple properties (e.g., author and publisher) without having to duplicate the whole data (but you could use a mixed way, too).
Example for the former way:
<script type="application/ld+json">
{
"@context" : "http://schema.org",
"@type" : "WebSite",
"publisher" : {
"@type" : "Organization"
}
}
</script>
Example for the latter way:
<script type="application/ld+json">
{
"@context" : "http://schema.org",
"@type" : "Organization",
"@id" : "/#org"
}
</script>
<script type="application/ld+json">
{
"@context" : "http://schema.org",
"@type" : "WebSite",
"publisher" : {"@id": "/#org"},
"about" : {"@id": "/#org"},
"mainEntity" : {"@id": "/#org"},
"author" : {"@id": "/#org"}
}
</script>
(where /#org is the URI that represents the organization itself, not just a page/site about or of the organization)
Providing WebPage
You can provide a WebPage item for each page. It can be helpful in many situations. But like it’s the case with any other type, too, there is no requirement whatsoever.
If you want to provide such an item, using the more specific types (like SearchResultsPage) where applicable is of course preferable. But if that’s not possible, using WebPage everywhere is way better than not providing it all.
In your case, you would have to decide in which syntax to provide it. JSON-LD would allow you to provide it as hasPart of the WebSite according to the former way, as explained above. But that would make it hard to connect the WebPage with your page’s main entity (which you specify in Microdata) via the mainEntity property. As I think this is an important relation, I would specify the WebPage in Microdata and connect the WebSite and the WebPage via URIs.
You could do this from the JSON-LD WebSite node with:
"hasPart" : {"@id": "/current-page.html"}
(You could also do this from the WebPage Microdata with the inverse property isPartOf, but then you’d have to provide an @id for the WebSite.)
Having the WebPage in Microdata, e.g., on the body element, it allows you to provide the mainEntity property:
<body itemscope itemtype="http://schema.org/WebPage">
<article itemprop="mainEntity" itemscope itemtype="http://schema.org/Article">
<!-- for an article that is the main content of the page -->
</article>
</body>
<body itemscope itemtype="http://schema.org/SearchResultsPage">
<ul itemprop="mainEntity" itemscope itemtype="http://schema.org/ItemList">
<!-- for a search result list that is the main content of the page -->
</ul>
</body>
Connecting WebPage and Organization
If you prefer, you could explicitly state that the Organization is the publisher/author/etc. of the WebPage, too:
<link itemprop="author publisher" href="/#org" />
(It could be deduced because you state this for the WebSite and every WebPage is connected via hasPart, but this is probably too advanced for many consumers, so stating it explicitly could help.)