[Captivate Q&A, Help & Troubleshooting] bcflyfisher:
Here's an update of what I did just in case it's helpful to someone else down the road.......

I did my best to follow the suggestions given by 4-2ndtwin in the 2nd post. I generally have pretty good backups of everything done but I did new ones just for kicks. Nandroid, Titanium Backup, efs, SMS, call log, APN, and a few other things. I downloaded all the necessary files, and laid them all out sequentially on my screen so I wouldn't get distracted and screw up. In the end I'm pretty much exactly where I wanted to be but of course there were a few unexpected issues.

- The Heimdall One-Click of stock GB with bootloaders was very easy. I had Samsung drivers on the computer already but Heimdall insisted on installing new ones. After that it did its thing and I was on official KK4 with GB bootloaders.

- Next up was regular Odin flash of the Corn Kernel. When I connected the phone in download mode Odin didn't give me a yellow light. If I connected the phone while it was NOT in download mode Odin recognized it. I wasted at least an hour to discover that it was just a driver issue. The drivers that Heimdall wanted weren't "good enough" for Odin. Interestingly, neither was the original package I had on the computer. The one that worked was called "Samsung_USB_Driver_for_Mobile_Phones.zip" from the Samsung website. After installing that Odin saw my phone in download mode and I was able to install the Corn Kernel. Rebooting into recovery gave an option to root the phone.

- At this point everyone in the world decided they needed something from me so between work and phone calls/texts I ended up using the phone on GB for a while.

- My boot screens had been a total mess since my first custom rom so I decided to do the boot screen fix next - http://xdaforums.com/showthread.php?t=1065743 - TRusselo added a bunch of good info to the thread and there's a good post on page 10 from irishvandal that explains the whole sequence of boot screens and what you can and cannot change.

- So the next step should have been to flash CM9 on my way back to SlimICS just like I did a month ago. I figured since I had been using the phone for a couple of hours I should wipe everything ... so I did the cache, data, format system, dalvik cache, and then I went to flash CM9 and noticed that for some reason I didn't have the zip file on the phone any more. I must have deleted it myself because nothing else spontaneously disappeared. When I rebooted normally to plug the phone in and transfer files I discovered that in wiping/formatting I messed something up and I kept getting stuck on the Corn Kernel boot screen. I could get into recovery or download mode just fine, just no normal boot. I was able to mount storage in recovery but when I tried to copy over the CM9 zip it kept hanging. After numerous attempts I decided to just go right back to the beginning.....

- Heimdall once again wanted its own drivers. No problem, I did that, then uninstalled them and reinstalled the drivers Odin likes, then got Corn again, did the boot screen fix again just to try a different image, then downloaded a new CM9 Nightly and copied it to the SD, flashed it with no issues, then flashed SlimICS (which actually has 2 zips plus addon packages) and I was back to ICS with GB bootloaders. It's amazing how fast things can be done when there are no more surprises!

- When the phone was rebooting into Slim ICS I got a message I don't remember seeing before - "Android is upgrading" or something similar. Weird. The next time I booted to recovery to try to restore the nandroid backup I ended up in CWMR Touch v5.5.0.4, which is weird looking and makes me feel strange. When I tried to do a full restore it encountered a few issues such as not being able to restore data normally. I don't recall the details but when I reinstalled Titanium Backup it would just FC so I couldn't restore any of my other apps. The "solution" was to reflash the Slim zips and do a restore of the system only. This set up all the tedious stuff for me. I got TiBu again and restored apps+data and that worked. Chose my launcher and it was back almost the way I wanted it. Interestingly, I had to replace the widgets but the shortcuts were all there in the right places.

- Voice search force closed. Slim doesn't include it in the base rom but it's available as an add-on and I had the zip on the sd from last time but flashing it didn't fix the problem (it had worked the first time I installed Slim). Some random sequence of freezing the Voice Search app, wiping its data, reflashing the Voice zip, unfreezing the app and it worked. In the process I noticed that in TiBu it was originally listed as Voice Search 2.x.x but then it was suddenly 3.x.x with a different icon. Then an hour later after all kinds of restoring (SMS, call log, etc) voice was force closing again. It was also listed as 2.x.x. This time it took me twice as long to randomly do things until it started working again (and at the same time it turned back into 3.x.x. It's been fine since...

So again a huge thanks for the advice! I got to spend the better part of a day fighting my way through minor issues but I learned a lot about my phone and got over my aversion to Odin for the last time. Hopefully someone else can benefit from something I've gone through. If nothing else, I feel a renewed sense of accomplishment.