Proper format for Google Schema? - schema.org

Question

I've been experimenting with Google Schema and I've looked at a few code generators and they vary in design. The link I'm using for info for these examples: http://schema.org/Book
1) When is it proper to use itemscope itemtype="someSchemeURL.org" or an actual href?
Example:
<div itemprop="author" itemscope itemtype="http://schema.org/Person">
or
<div itemprop="bookFormat" href="http://schema.org/bookFormatType">
The second example isn't even valid HTML since the href attribute isn't accepted on a div.
2) For the example above, is the first column always an itemprop and the second column always the itemscope itemtype?
3) If there is no itemscope itemtype specified, does the itemprop default to the parent itemscope itemtype?
Example:
<div itemscope itemtype="http://schema.org/Book">
<div class="book" itemprop="name"></div>
<div itemprop="author" itemscope itemtype="http://shema.org/Person">
<div class="author" itemprop="name"></div>
</div>
</div>
The .author class will result in the name attributed to "author"
The .book class will result in the name attributed to "book"
So this would mean that although multiple itemprop's have the same name, the itemprop always applies to the parent element, correct?
4) Where is it specified when to use meta, link, span, or div? Or is this left up to preference?
Example:
<div>
<meta itemprop="datePublished" content="2013-07-01">
Some text
</div>
<div>
Some text
<link itemprop="bookFormat" href="http://schema.org/bookFormatType">Ebook
</div>
The second example is invalid, I know, but it's an example from one of the code generators. That specific generator produces invalid code so I know not to use it, but where are they getting their idea to use a link tag (albeit incorrectly)?

Answer 1

These docs can answer almost all of your questions. Maybe you've already seen them but just in case.
Microdata Spec
Getting Started Tutorial at Schema.org
So answers for your questions in order they appear:
1.The first one is correct. The official microdata spec tells us
Microdata is most useful, though, when it is used in contexts where
other authors and readers are able to cooperate to make new uses of
the markup.
For this purpose, it is necessary to give each item a type, such as
"http://example.com/person", or "http://example.org/cat", or
"http://band.example.net/". Types are identified as URLs.
The type for an item is given as the value of an itemtype attribute on
the same element as the itemscope attribute.
Example
<section itemscope itemtype="http://example.org/animals#cat">
<h1 itemprop="name">Hedral</h1>
<p itemprop="desc">Hedral is a male american domestic
shorthair, with a fluffy black fur with white paws and belly.</p>
<img itemprop="img" src="hedral.jpeg" alt="" title="Hedral, age 18 months">
</section>
2.No. Itemprop is used to indicate property of some entity. Itemscope - entity scope. And itemtype - type of the entity. These are different tags with different meaning which can be used separately (at least in theory). What doc says:
At a high level, microdata consists of a group of name-value pairs.
The groups are called items, and each name-value pair is a property.
Items and properties are represented by regular elements.
To create an item, the itemscope attribute is used.
To add a property to an item, the itemprop attribute is used on one of
the item's descendants.
And examples
<div itemscope>
<p>My name is <span itemprop="name">Elizabeth</span>.</p>
</div>
<div itemscope>
<p>My name is <span itemprop="name">Daniel</span>.</p>
</div>
3.Even when itemscope itemtype are specified along with itemprop it is still property of the parent type. In this case this property is entity itself. And you're correct with your example: names will go to different entities. Here is what doc says about processing properties.
The property value of a name-value pair added by an element with an
itemprop attribute is as given for the first matching case in the
following list:
If the element also has an itemscope attribute The value is the item
created by the element.
If the element is a meta element The value is the value of the
element's content attribute, if any, or the empty string if there is
no such attribute.
If the element is an audio, embed, iframe, img, source, track, or
video element The value is the absolute URL that results from
resolving the value of the element's src attribute relative to the
element at the time the attribute is set, or the empty string if there
is no such attribute or if resolving it results in an error.
If the element is an a, area, or link element The value is the
absolute URL that results from resolving the value of the element's
href attribute relative to the element at the time the attribute is
set, or the empty string if there is no such attribute or if resolving
it results in an error.
If the element is an object element The value is the absolute URL that
results from resolving the value of the element's data attribute
relative to the element at the time the attribute is set, or the empty
string if there is no such attribute or if resolving it results in an
error.
If the element is a data element The value is the value of the
element's value attribute, if it has one, or the empty string
otherwise.
If the element is a time element The value is the element's datetime
value.
Otherwise The value is the element's textContent.
The URL property elements are the a, area, audio, embed, iframe, img,
link, object, source, track, and video elements.
4.Left up to preference. There is general advice from search engines - markup consumers
However, as a general rule, you should mark up only the content that
is visible to people who visit the web page and not content in hidden
div's or other hidden page elements.
Schema.org doc gives good overview when usage of hidden elements may make sense.
Many pages can be described using only the itemscope, itemtype, and
itemprop attributes (described in section 1) along with the types and
properties defined on schema.org (described in section 2). However,
sometimes an item property is difficult for a machine to understand
without additional disambiguation. This section describes how you can
provide machine-understandable versions of information when marking up
your pages.
Dates, times, and durations: use the time tag with
datetime
Enumerations and canonical references: use the link tag with
href
Missing/implicit information: use the meta tag with content.
Check this link for details.