Hi,
Though I’ve seen and solved myriad menu display problems, this is a new twist.
I have not used the &limit parameter much. AFAIK, this parm will affect your whole menu, not just one level, and I would guess that this is why parts of your menu vanish when using it; maybe a level above the last one has more than the limit, and is being chopped off.
Using Ditto for this... hmmmm... sounds tough. Of course, Ditto easily allows you to control how many docs are displayed, but I have not seen a way to "class" the current item. (if someone knows, great!) If I had to do this with Ditto output, I would probably consider using JQuery, which is a fair bit of work, probably overkill, and way off-topic.
This isn’t as precise, but I wonder if instead you might want to make use of the "Publish Date" and "Un-Publish Date" to handle which ones are showing. Or if your client is in there editing often, maybe they’d be willing to do manually use Publish and Unpublish, or maybe Deleting old docs. Then Wayfinder can handle "active" items.
Good luck, Dave