The lib seems to be in the correct place (for an ubuntu package).
You're a bit out of luck though, the ubuntu version you have wont work with oxc (nor does any of the other packages supplied with 16.04). So even if the loader could locate the correct version of libyaml-cpp.so.0.5 (yes they can differ) you would have been presented with a different error.
The only way you can play oxc on 16.04 is by getting your hands on the correct version (for regular oxc it is 0.5.x, where x != 2, i don't know if extended needs a newer version). either by finding a ppa or by building libyaml yourself.
Alternatively you can try asking nicely if a version can be build with statically linked libraries (which is something i have no experience with).
I am still puzzled by the loader failure though. Could you provide me with the output of the following command?
ldd -v OXC_binary | grep yaml
where OXC_binary is the full path to your downloaded version.
Thnx