And the solution:
On the KwikStik-K40 V5 board, the silk screen labels for UART5 TX and RTS are REVERSED! As soon as I moved my probe over to the RTS pin, I saw the serial data screaming across as it should.
From continuity checking my KwikStik V5:
TP labeled as "RTS" is connected to pin A44 of the tower connector "PTE8/UART_TX".
TP labeled as "TX" is connected to pin B21 of the tower connector "PTE7/UART_RTS".
TP labeled as "RX" is correctly connected to pin A43 of the tower connector "PTE9/UART_RX".
TP labeled as "CTS" is correctly connected to pin A9 of the tower connector "PTE10/UART_CTS".
I assumed by V5 of a board, Freescale would have the basics checked out, and that a non-functioning port would be my own software mistake. I am still assuming this was my issue with UART4 as well... Maybe I'm wrong?