Update: I found a very simple 'fix'- switching from 'UBBT70 - Dark' to 'UBBT77 - Dark' resulted in all of the various "Smilies" to display as intended. Yaye!
It didn't matter what browser or iteration I used, before or after any updates of anything,
the problem persisted- until I tried changing the display "Style".
FWIW, I do prefer the 'UBBT70 - Dark' over the 'UBBT77 - Dark', but it's a small compromise in exchange for properly functioning and displaying "Smilies" here 'bouts, trivial as that may seem. Please let me know if that changes, thanks!