Gwen,   I don't have the CEntrance program, but I've still got my thinkin cap on.  Gonna be hard to come up with something these guys ^ haven't covered.
 
Try this just to rule it out-  Click the PDC button and the FX button (turn them off).  See if that improves anything.  (I don't think that suggestion has been made yet, has it?)    

its working!!!!

driver settings:       imgur.com/dZxYeZ0
sync and caching:   imgur.com/ACh6u8P
repeatedly bounced back click track:  imgur.com/Pz2OA9N   ---- increasing in amplitude to the point of clipping and distortion, as it should be!
drum pad, played to metronome, bounced back with metronome and in perfect time:  imgur.com/HQpk0qe
 
thank you so much!!!  i have no.  freaking.  idea.  how I missed that.  I was trying everything I could before to get it so I could run youtube videos or external MP3 players while playing without messing up my sound, because sonar wouldnt share with anyyyything on WDM.  None of the other settings were working that day!    I guess it was some sort of fluke.  I guess the lesson I've learned is that even computer settings can be finicky and deserve twice-overs.
 
On the upside, I've learned lots of nice tricks.  Thank you for all the people that were so vigilant in helping me figure things out :)
 
I thought it was very odd that cakewalk wouldn't include some sort of roundtrip test and automatically account for this, but there it is.  automatically adjusting for the 661 sample latency :)
 
i'm so happy right now.  AHHHHHHH
 
^_^ thanks guys
 -gwen!
 
ps;  i am ay freaking oh kay now.  but if you're just more of a tinkering and figure-things-out-er than just wanting to help really bad type... CEntrance is getting about 46 more samples than sonar ;) 

Cool. Glad you finally got there.   Figured something basic wasn't right. That 46-sample difference is what you want to enter in the Manual Offset field in Sync and Caching to compensate that extra bit of "hidden" latency that isn't being reported to SONAR by the driver. That's a pretty typical discrepancy, mostly attributable to A/D conversion time. Once you do that, your re-recorded tracks will align with the original to the sample.