Jeff,
This is a community forum with voluntary participation. The answers are not guaranteed and there is no need to get aggravated if you don’t get yours.
As the product designer I try to answer the general Digirig questions, but I don’t have exact settings for every combination of transceiver/mode/software and OS.
In your case, it is likely that the IC-718 does not support PTT command over CI-V/CAT. Configure PTT to be triggered by RTS of Digirig’s serial port even if you have CI-V/CAT otherwise configured and working. Less desirable PTT option is by VOX.
As for changing “frequency, mode and power”, I’m not sure I understand the question. Omnirig facilitates CAT control, but I don’t remember seeing user interface for these functions there. Do you refer to flrig?