Very strange. I installed LibreOffice-fresh from Manjaro-application-utility with open-jdk (first choice) during installation packages. I received these errors when I launched the application:
“javaldx failed!
Warning: failed to read path from javaldx”
Then I removed LibreOffice-fresh and I reinstalled it with pamac, and I tried openjr8 as choice. I didn’t have these errors above but LibreOffice don’t start.
In the ~./config directory, I don’t have libreoffice directory.
Can you try to install unoconv with libreoffice-fresh 7.0.3-2 ? Because I installed it during the first installation with LibreOffice-fresh.
Note: look that discussion here, here and here.
I will give you the result of strace soffice command or libreoffice --strace 
I created another user and I will try to launch LibreOffice-fresh with him.
Regards.
Edit: With the other user, I’ve got the same errors. 
libreoffice directory is available in the ~/.config directory of the 2 users.
Unoconv package is not installed.
The libreoffice -v command give me this result:
terminate called after throwing an instance of ‘com::sun:
:uno::DeploymentException’
I send you the strace.log messages in PM.