IMO it is overkill to use wayfinder for the top-level menu since it is pretty much a static output with oly the active class changing. Create a smile menu snippet just for this. You can use the same logic as UltimaeParent to make it have the active state. I have done this many times...let me see if I can find a version that I can share.
Here is one...in this example you state the ids of the top level menu (and a custom id for individual styling...this was needed for this particular menu).
[[MenuBuilder? &docs`1,home|2,about|3,contact` &title=`longtitle`]]
doc id 1 will have id=’home’ added to the output, doc id 2 will have id="about’ added...and so on (there are 100’s of ways you could do this differently). Then it uses the UltimateParent snippet to find the top-level parent and apply the active class accordingly. This sort of alternative menubuilder is only a few lines of code.
<?php
// Build simple list menu based on array of doc ids
// sample call: [[MenuBuilder? &docs`1,home|2,about|3,contact` &title=`longtitle`]]
$docs = isset($docs) ? $docs : '';
$docId = explode('|', $docs);
//$activeId = '2';
$activeId = $modx->runSnippet("UltimateParent", array("id" => $modx->documentIdentifier, "topLevel" => "1" ));
$title = isset($title) ? $title : 'pagetitle';
$output = '';
$output = "<ul>\n";
foreach ($docId as $doc) {
$d = explode(',', $doc);
// get doc parent
$thisDocParent = $modx->runSnippet("UltimateParent", array("id" => $d[0], "topLevel" => "1" ));
// get document title
$y = $modx->getDocument($d[0], $title, 1);
if(($d[0] == $activeId) || ($activeId == $thisDocParent)) {
$output .= "<li id='$d[1]' class='selected'><a href='[~$d[0]~]' title=\"$y[$title]\"><span>$y[$title]</span></a></li>\n";
} else {
$output .= "<li id='$d[1]'><a href='[~$d[0]~]' title=\"$y[$title]\"><span>$y[$title]</span></a></li>\n";
}
}
$output .= "</ul>\n";
return $output;
?>
Note: this is just an example of the possibilities...this was built for a specific site so it may not be what you need, but it is a good starting point. Hope it helps (and that I understood the question)