I have been having trouble with CAT control as well, trying to use WSJT-X as well as JTDX. There are 2 selections within OmniRig that I can use - FT847 and FT847 (UNI) which I believe would stand for unidirectional. I can get the UNI setting to work, sending commands to the rig, but am unable to get the rig to send it's status back to the laptop.
I am about at my wits end, and will probably use a different rig with better CAT control...
Micky K1XH