Thanks Ricardo and Vincent. I think I have some answer on my questions except this one:
4. I like the idea of supporting office app clients. But it seems there is some clumsiness with XOffice specifying a parent: http://jira.xwiki.org/jira/browse/XOFFICE-243 And I can't find any documentation on editing/creating content from OpenOffice and/or via any webdav client. Things like URL conventions, etc. This page http://platform.xwiki.org/xwiki/bin/view/DevGuide/Architecture mentions XOO (Xwiki OpenOffice) but there is nothing else about it: http://www.xwiki.org/xwiki/bin/view/Main/Search?text=XOO&wikinames=&space=
also, http://code.xwiki.org/xwiki/bin/view/Plugins/SortedDocumentTreePlugin says: use imported class (section Installation step 3) called XWiki.SortedTreePageClass where can i read what that means? (what is importing a class?) btw, it occurs to me that the support for section editing makes it viable to use longer pages, which will help with both page ordering and with export to PDF. -mda