Eureka! Thank you all for your collective inputs. Though I did not find success in using your exact recommendations your comments led me to these solutions:
I solved the TV input switching issue simply by increasing the delay time in the macro after the Plasma power on command to enable the media box to go through its start up process. Specifically, I inserted two time delays of 3 sec & 1.5 sec after power on command then moved the input command further down the macro. The second time delay was inserted after the receiver power on and device commands.
The Yamaha sound setting issue was resolved by using the IR Data Navigator to drag the desired setting into the macro and INCREASING the REPEAT number to 6 from 3.
The system off command was also resolved by using the P-Off commands found within the pages of the respective devices and using those in the macro.
My short 'beta' test on the TV macro seems to be working fine; I will mirror these steps for the other devices. I'm keeping my fingers crossed.
