I don’t think the op was referring to the character’s behavior. Every time I watch a rerun of Andy Griffith and Howard is in it the first similarity to me is the voice. I also think his facial features resemble Bert’s.

Howard was an irritating character, at best. Whenever he is a large part of an episode, I turn the channel.

So you missed the episode where Howard's Mother gets remarried, moves away, and Howard turns their home into a 'swinging bachelor pad'!!
It is epic in its' failure to BE swinging at all.
I don't mind Hoaward being all those things you say (he is) but I think that's what the show is aboutreal characters and how they manage to get along with the rest of the town. Now Barney Fife makes Howard look like an amateur when it comes to bragging and getting things wrong. But we love him anyway (he's hilarious!)

Stupidest thought I have ever heard. Of course, everyone knows that Bert & Ernie were based on Bert & Ernie from the movie, "It's a Wonderful Life."
On Andy Griffith and Mayberry RFD, IMO, Howard was a braggot, know-it-all, name-dropper, and socialist, who tried using the Mayberry council to force private resident and business owner, Goober, to dig up his newly paved parking lot, at his new gas station, just because Howard wanted the glory of finding a dinosaur skeleton. He trespassed, and destroyed private property, and should have stayed in jail, when Goober put him there.
In another episode, Howard should have been put in prison for armed robbery, for robbing the Mayberry bank, because he thought Goober wasn't doing his job. Goober caught him, but the rest of the council members made Goober release him, with no consequences, at all. Had it been anyone else, who robbed the bank, with a gun, and a ski mask, they would have the book thrown at them.
Howard was an irritating character, at best. Whenever he is a large part of an episode, I turn the channel.

The characters of Bert and Ernie were based on two characters in the "IT'S A WONDERFUL LIFE" movie staring Jimmy Stewart. Not their looks, but their names. It i my understanding that their looks were thought up by Jim Henson

No, I never heard that but I think it's an absolutely charming thought!
I'm sitting here tonight watching the Andy Griffith show on TVLand because all of my "usuall" tv shows are re-runs that I don't particularly care for (come on! Simpson's version of 24? something else, please!) and while watching the show I am searching for info on EVERYONE in the cast. (I am loving Hope Summers, btw.)
Anyway, I think if Ernie was, in fact, based in Howard Sprague, then no wonder we all love him, and Howard too, and I think the Sesame Street writers were genius.