out of curiosity, have you tried a different skin, confluence comes installed with osmc, just not activated. Not too experienced at reading logs, but it looks like it is having trouble loading the osmc skin files.
ssh in and try:
sudo nano /home/osmc/.kodi/userdata/guisettings.xml
my skin is called mimic. find the section as below and change skin.mimic (or in your case skin.osmc) to skin.confluence
false Default skin.mimic SKINDEFAULT SKINDEFAULT 0 resource.uisounds.confluence 10000
then ctrl+x and y to save
if this helps perhaps it is possible to uninstall the osmc skin and reinstall it? or who knows, maybe try out some other skins from all the great skinners out there.
Or I could be completely wrong (not unheard of )
if this doesn’t help simply reverse the process changing skin.confluence back to skin.osmc if you like