I was trying to clarify what I was doing that was affecting the remote but didn't type enough to clarify. <sigh> (so I'm an idiot). Yeah, Aux 
is DVR. Apparently I keep forgetting steps or pressing the wrong buttons, hence why I keep getting frustrated!!
It was like some buttons weren't changing modes when I switch modes.
I activated the extender (TV Power), then pressed something like this:
aux - stop
cbl - stop (wasn't working cbl device but still working aux device for the lower buttons)
vcr stop
cbl stop (was then sending out vcr commands for lower buttons)
Yeah, I 
somehow must've been once again using the original remote image that didn't have the extender installed, hence why some buttons weren't working as intended?  
 
Anyways, I decided to 
yet again start fresh and create "new" in RMIR, triple-checking I'm making the correct choices every step of the way and it seems to work fine now.
Anyways the Roku is at least working fine now. It's hard to fully test the remote as that TV is being watched almost 100% of the time so it's difficult to get a chance to do testing...
Back to stereo multiplexer thing:
I decided to check the Macros tab in the remote image I was working with (before getting back to the stereo multiplexer project and discover I *still* have nothing listed in the Macros tab?!?
AHHH! I'm going to scream.
Ok, so when I create a "new" Remote image in RMIR, I obviously have to install the extender at some point later, even though I chose "URC-881x x3 2K (6_80_2x3)". I mistakenly thought it automatically installed the extender since I chose that. <sigh> Another mistake on my part.
Ok, we are now on the same page. (I think?)
Thank you for your patience. You're a saint 
 
As for the multiplexer thing, if the original remote ever dies, I think I'll just get a 4 device universal remote and program each mode on a different device and be done. That multiplexer thing is way over my head. I'm having a hard enough time doing simple things (like keeping an extender installed!).  
