Failed to get default contexts and file mode for storage files
I posted this question over at the XDA developers forum and we have it figured out, if not completely resolved. Turns out the TWRP error was something introduced in the version 2.8.3.0, but is not present in previous versions. I have a different TF700t that had version 2.8.1.0 installed (the version immediately before the error came in). It did not have the error, but when I upgraded it to 2.8.3.0 the error appeared. When I downgraded the TWRP on both my devices to 2.8.1.0, the error went away on both. 

Team Win released version 2.8.4.0 a few days ago, so I tried installing it. Unfortunately, it still displays the error. 

As for the F2FS error, I found out that you should only convert the /data location to F2FS. The /system and /cache locations should stay at EXT4. Once I changed this, the install went thru just fine using F2FS.