without looking into the details: if you use for an xowiki instance a custom adp template, you can add at the appropriate place an adp-include into the .adp file containing the bars. i guess, this is the cleanst solution for what you are describing.
when you change the view method - which i would not recommend in your use case - be aware that xowiki passes explicitely the variables as context to the template (if you want, the reverse part of a page contract) in return_page.
none of the includelets are designed to filter out some content in some languages depending on preferences. If this is wanted, it should be done on the SQL layer, since e.g. the categories includelet supports e.g. counting; if you know an efficent way to do this in SQL, we can add this to xowiki. if you are looking for a quick solution for your site, i would recommend to alter the category renderer in the portlet procs to filter out the stuff, you do no want. But please, DON'T commit this to CVS.
