I don't believe the identities are known. Else they would have been able to have given their exact ages in the indictment.
Just on the point of the middle aged "italian" woman, this doesn't form the basis of the latest charges. There were inconsistencies in the accounts of Manfred and Helge over her description and the location of the rape. In the latest charges, they have gone with the description that Helge gave of an older british woman in a holiday apartment. Presumably they see his account as more reliable, and he is the more key witness, since he viewed a lot more of the tapes and claims there were recordings of that same rape made from multiple angles. Whereas Manfred claims to have only seen part of it, very briefly, and from only one angle. His assertion the woman was italian was based on hearing one word which he interpreted to mean "help" in italian, nothing about an accent. Of course, he may have simply misheard what she said, whereas Helge having seen the rape twice from 2 angles claims the woman called CB obscenities in English and with a British accent.