You could do bitwise as well if iPad is the main focus. However I think that the problem is that the original AV contractor could have done a better job. Yes, there are discrete commands for Denon Hdmi out 1 and 2, at lease with the 4311, I just did this twice in the last two months with URC IP control.

If the system isn't turning on and off correctly and the original contractor doesn't know how to set up the AVR, it may be that they aren't that good. I'd let them try to fix it, I wouldn't pay more for it, especially if they are new to C4 and are learning on your house.

Or you could put in a Prodigy system, and make them take the C4 back if they can't deliver a functioning system.