Btw, I don't see Google XML Sitemap Admin in admin/Config, just in admin/Tools, but it's ok, it works fine.

My question is:
Google sitemaps asks me, when trying to add
sitemapindex.xml
as a mobile sitemap, what markup language I should choose. The 3 options are:
XHTML mobile profile (WAP 2.0)
WML (WAP 1.2)
cHTML (iMode)

I don't understand what these are, any idea what to choose? I have ZC v.1.3.7

Or should I add General Web Sitemap?

Adding just sitemapindex.xml is enough, right? No need to add the other two .xml files, for categories and products , right? ...