OK, thanks. Here's where I see the proposal to be (in terms of what can be done now and what will receive approval from one of the gods):

Code

No action: Remove from proposal.

WBR

Action point: A small documentation change to Perl Monks Approved HTML tags. [See below.]

Spoiler

No action: This never was part of the proposal ("I'm not suggesting any changes to the remaining non-standard elements: <spoiler> and <readmore>.").

Other attributes

Action point: Add the attributes class, dir, lang and title to the elements as described in the table in my OP.

For the wbr documentation change, this might save yourself (or someone else in pmdev) a bit of work.

In the table, change

wbr
[download]

to

wbr<sup>5</sup>
[download]

Add to the end of the existing notes:

<p>
<sup>5</sup>The <c>wbr</c> element provides a <em>suggested</em> 
wrapping point for long strings that contain no whitespace. See 
[http://www.w3.org/html/wg/drafts/html/master/semantics.html#the-wbr-e
+lement|W3C: The <c>wbr</c> element] 
for more information.
</p>
[download]

Obviously, I don't have access to the code for adding attributes to the existing elements; however, if that turns out to be a lot of work (due to the large number of element/attribute combinations), and you'd like an extra pair of hands, just let me know.