There’s a misplaced comma in my original much-maligned post, also. 
Actually, iirc, the Star Trek fotonovels didn’t have word balloons, rather they had dialogue in a block format with a straight line drawn to the character. I just used word balloons as a bit of short-hand.
Anyway, back to initials… please…
Sir Rhosis
On One Day at a Time, Pat Harrington’s character was building superintendent Dwayne F. Schneider. On one episode, he was asked what the “F” stood for, and hesitated before admitting his middle name was “Flo”, a tribute to impresario Florenz “Flo” Ziegfeld of Follies fame.
When interviewed, actor E.G. Marshall gave numerous answers to the question of what his initials stood for. As the linked page says, he was born Everett Eugene Grunz, but suggested at various times that E.G. stood for Edda Gunnar, Enigma Gregarius, or Everybody’s Guess.
H.M. Murdoch & B.A. Barracus.
(I don’t think the H.M. was ever explained)
“Howling Mad”.
Quite right. And as I understand it, B.A. Barracus was short for “Bad Attitude.”
Of course, Howling Mad and Bad Attitude might just be nicknames made up by the rest of the A-Team, too. Guess we’ll never know. 
What about I R Baboon?
Officially, it was “Bosco Albert Baracas.” In episode “Lease with an Option to Die,” B.A.'s mom, played by Della Reese, calls him by his given names.
On Andy Griffith, Barney was given several different middle names/initials. Don’t recall if they ever settled on one in particular.
And still nobody has said what the “P” in Alex P Keaton stood for…
Another one that hasn’t been mentioned: On Cheers, Woody Boyd’s middle name was Tiberius. Just like Jim Kirk.
I don’t think they ever said what the C stood for in Clifford C. Clavin.
What does the T in Mr. T’s name stand for? I never heard it mentioned. How about the fantastic animal on The Howdy Doody Show with the name of Phineas T. Bluster? Any connection with P.T. Barnum? There was a sitcom, starring Burl Ives, entitled O.K. Crackerby. Any guesses?
I think Mr. T was born Lawrence Tero.
Barney P. Fife and Barney Oliver Fife. I think they used the P. initial (don’t remember what it stood for) more often than the O.
Sir Rhosis
In an episode where his high-school yearbook was visible, the caption by his picture referred to the bumbler as Bernard Milton Fife. I remember seeing that installment of the series, but not any on which Barney’s middle name was said to be [www.mix95.com/artieans5.asp+%2B+“Barney+Fife”+%2B+“Milton”&hl=en&ie=UTF-8]Tibbs](http://64.233.161.104/search?q=cache:ZbPVFIa9bZYJ:[url).
Anyone else find it suspious that her middle name is “Jo.” Particularly since she looks so much like Joey, and not at all like her 'father" Danny.
Comedy Central used to have a show called Beat the Geeks where contestants would match pop culture wits with various experts (the Geeks)
The TV geek once told a story of how he was asked what the D in J. D. Clampett stood for. He couldn’t think of any episode of The Beverly Hillbillies which explained it so he talked to the producer who couldn’t think of it either so he called Buddy Ebsen. Buddy decided it should be David.