Although nobody replied, I share the result of my experiments. You have to know, tehat on huwiki we introduced FlaggedRevs ( http://www.mediawiki.org/wiki/Extension:FlaggedRevs).
Now, getVersionHistoryTable() and getVersionHistory() give back only the unrevised versions, and none of the revised! fullVersionHistory() seems to work correctly for each version IF the page has ANY unrevised versions; but it results in an "out of range" error if the page has only revised versions. None of these methods gives the edit comments. In getVersionHistoryTable() they appear as <nowiki></nowiki>, and in getVersionHistory() as u''.