So here is the latest update in my custom rom saga ...
I downgraded TWRP to 2.6.1 .. and attempted to re-flash both SEAL and RocketTab. Both installs seemed to complete without any errors this time, but after rebooting, my device froze on the Samsung Galaxy Tab logo screen .. before the boot animation. This happened for both the SEAL and RocketTab roms. I also no longer got the not rooted error message, so it looked like it was fine.
Any thoughts on why these custom roms are not booting? I appreciate the help.
I restored back to my de-bloated stock backup, and it works fine. A little faster definitely, but not speedy by any means.