Hi, @Dingo .
Um.....short answer? No, I can't. And I can't figure it out, either.
I have the very newest LibreOffice (v7.6.2.1) running, as a portable, in both the older Tahrpup64 AND the newer Bionicpup64. But for some inexplicable reason, the newest LibreOffice I can persuade Xenialpup64 to run is 7.0.3. Crazy, huh?
Anything newer, and I get exactly the same terminal complaints as you've posted above. I DO have Java installed in every one of my Pups, as a matter of course, but it doesn't make a scrap of difference to LibreOffice in Xenial. I've given up worrying about it..! 
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If you still want an up-to-date office suite to run in Xenialpup64 - as a 'portable' - from this same 'stable', then I would recommend doing what I've done. Use the latest OpenOffice-portable I put together just a couple of weeks ago. A bunch of us were discussing it here, and I learnt from OscarTalks the simplest way to install the thing (and then turn it into a portable, 'cos it comes as around 45 tiny little .deb packages, all of which have to be installed separately!)
viewtopic.php?t=9752
I then built the portables - both 32- AND 64-bit - which can be found here:-
viewtopic.php?t=9758
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If you're used to LibreOffice, you'll be at home with OpenOffice straight away. Several years ago, the OpenOffice devs had a whole series of big disagreements between them. The upshot of this was that a bunch of them left, went their own way, forked the OpenOffice code & produced LibreOffice. So, in a way, OpenOffice is LibreOffice's parent.......and despite that the two have varied somewhat in the way they handle things, the layout, the appearance, and the way everything works, has barely changed at all.
This is the current, up-to-date release - v4.1.14 - and although it's a few months old by now, is capable of working with the newest M$ .docx formats. (The OpenOffice devs are not quite as crazy keen on continuous updates as the LibreOffice crowd.....but it's a decent L.Office alternative, for all that).
As usual, it's entirely up to you. This is the way I've worked around it with Xenialpup64. You may wish to find another option, but this way is certainly "usable", for all that.
Mike. 