Okay. Seems like you have 2 questions…
1. Can I use CMW to show the current menu item, with its children and its ancestors?
Yes, you can (Branch = Current Item, and Ancestors back to root).
2. How and where do I put the CMW instance on a category page?
My first advice would be to put the CMW widget into a widget area, such as a sidebar. That’s how CMW was originally intended to be used, and widget areas can be dynamically controlled (as in show or don’t show) using other plugins. Also, themes often provide styling for menus within their sidebars.
If you don’t have a suitable widget area, or can’t use the widget areas you have (for whatever reason) then consider creating one you can use. If you don’t have the skill, or inclination, to modify your theme, then there are various plugins that provide adhoc widget areas.
If you can’t use the CMW as a widget then you might be able to use it as a shortcode … if you have somewhere to place the shortocde. Shortcodes can be placed anywhere that your theme will handle. This usually means a post’s content, and often its excerpt. Text areas in widgets are quite often enabled for shortcode usage as well. And you can always code it directly (carefully!) into a theme’s template file. There are all sorts of places that a shortcode could be placed – such as Category Description – but whether or not it gets recognised, resolved, and output to the webpage, is down to your theme (and possibly other plugins).
On some of your category pages, you already have something that seems to display a list (UL.subcat) of child categories(?). I have no idea how that list is produced.
Since a category page does not have its own post content – because it displays excerpts from a number of posts – you’re going to have to find some other way of getting the shortcode onto the webpage. How you go about it depends on where you want the output to appear. If you want the CMW instance to appear in place of the UL.subcat that some of the category pages currently show, then I suspect/guess that you will have to edit a theme file (possibly a template file, or you might be able to hook into an action/filter from the functions file). Personally I wouldn’t try replacing UL.subcat, I’d just remove it and place CMW somewhere better suited and more easily stylable … but then it’s not my site.
So, bottom line is : Yes, CMW is perfectly capable of producing the filtered menu that you require. However, placement of the CMW instance within your webpage – whatever page that might be – requires a decision as to where you want it, possibly governed by your ability to get it there. That’s down to you, your client, your theme, and whatever other plugins you might find useful.
