It seems logical that adding the empty a href and span produces an extra line. When I change the chunk to:
<!-- rowTpl -->
<li[[+wf.id]] class="[[+wf.classnames]]">
<a href="[[+wf.link]]" title="[[+wf.title]]" [[+wf.attributes]]>[[+wf.linktext]]</a>
<a href="[[+wf.link]]" class="flyout-toggle"><span></span>[[+wf.linktext]]</a>
[[+wf.wrapper]]
</li>
I get a duplicate li for everything including the top level li items, even those without submenus. Before when I added the extra li with the flyout-toggle class and span, I was just seeing a blank li in the submenus.
I've added the css too. I can see it functioning in the Foundation doc page when I inspect it, although there's an important declaration added (border-left: 0 !important;) and the padding is 20px instead of 22px.
It has something to do with the wf.link and wf.linktext placeholders I think. Wayfinder is doing it's job and producing li items with text (for me)as it's being told to do. Twice, exactly as it's being directed. Removing wf.link and wf.linktext and leaving just the a href="#" or a href="" produces the same result.