The Mystery Cartoon Character Game, ongoing.

And the first two guesses are already on the list besides. So they don't really count.

Very true, you pointed that out earlier, and I mindlessly overlooked it. Fortunately, I edited that post to reflect your observation that Nibbles is ineligible. Once I return from dinner, I'll give three more clues that should lock this character down nicely.

Big Nose is ineligible, too. He's been on the used character list for quite a while. And I admit my mistake about Taz.

Well, it's time to clear up the mystery. Despite several close tries, nobody hit the mark; I'll take a modicum of pride in that.

4) In his first appearance, this character had no love for either of the title characters. Teamwork by the title duo was necessary to bring about this character's banishment.

5) Although this character seems to favor one character at the expense of the other, there were times when this character could be civil and cooperative with that other character.

6) This character gained a son. The wife / mother somehow remains invisible; perhaps cartoon children just *poof* into existence.

Aha! I know it for sure now. It's Spike, from the Tom And Jerry cartoons.

Yay, yes it is, good ol' Spike the bulldog from MGM's Tom And Jerry series.

Spike goes all the way back to "Dog Trouble" from 1942, and has been a consistent supporting character, even in the television adaptations.
There are cartoons where Spike says nothing, and others where Spike does all the talking while Tom and Jerry remain silent, as usual.
The voice of Spike was provided by Billy Bletcher until 1949. Thereafter, Daws Butler took over, adding a Durante-like speech pattern.
Spike is often an ally of Jerry Mouse, and functions as a thwart to Tom Cat. "The Truce Hurts" is one example of Spike cooperating with Tom.
Spike gained a son, Tyke.

Collect another +1, EmeraldIsle. And, let me ask: are you enjoying this as much as it sounds?

I certainly am. So much so that I decided to post these clues:

1. We're the boy and dog who accompany the title character.

2. Our adventures consist of five-part story arcs.

3. Our animated series literally provides lip service.

These must be Spinner the boy and Paddlefoot the dachshund from the Clutch Cargo series of cartoons. The "lip service" clue alludes to the Synchro-Vox device for averting the drawing of phonemes on the characters. The less said about that idea, the better.

OUB, you're right on all counts. So take a bow, and another turn. Great job.

Nifty, I'm finally making progress. So, time to find a new vein ... aha, this one is untapped, I'll try it.

1) Like Batman and Robin, this is a crime-fighting duo. However, these characters are very unlike Batman and Robin.

2) These two characters often drive to the scene, though they both can fly when they choose to.

3) Batman and Robin have the Batcave, the Fantastic Four have the Baxter Building. These two characters have ... an annex to a church.

Sorry. Can't put my finger on it. Thought I had it, but I was wrong. I now leave it up to the other players.

I don't know much about superheros, so I'm stuck on this one.

Could this be Ace and Gary, the Ambiguously Gay Duo?

Well, thank you Glowworm, for bending my head like that. Um, I can see where Ace and Gary are similar to Batman and Robin, right down to the ... um ... * ahem * Moving on, this duo has their own vehicle, and Ace can fly as well, though it seems Gary cannot fly. But I'm positive Ace and Gary's home / headquarters is not an annex to a church.

Dang, I really must start giving better introductory clues.

Thank you, Chief. If you'll recall, the original thread ran so long on the old Gossamer forum that the mechanism didn't know what day it was.
Perhaps it says something about us, in that we enjoy poking each other with cartoon factoids.

Yeah, it was just a far out guess to be honest--I had a feeling that third clue didn't match up well at all.

Well, now. There are only two characters left who match the clues perfectly: Basil and Dawson, from "The Great Mouse Detective."

Not bad; Basil of Baker Street and Doctor Dawson are a crime-fighting duo that are mice rather than humans. And they flew in a makeshift balloon to pursue the villain's airship. Although "driving" is an unusual way to describe riding upon a basset hound for overland transport. However, once again, we bump into the church annex requirement. Basil makes his home inside the walls of 221 Baker Street, either taking inspiration from legendary detective Sherlock Holmes, mimicking said character, or simply sharing a passion for detective work.

Clearly, it is time to ice these kitties.

4) These characters are produced outside of the United States. They are, however, strongly derivative of characters created by Craig McCracken.

5) Now, the silver age Brainiacs, when defeated by Superman, were rigged to explode so that they could not betray their creator. Likewise, most foes defeated by these two characters explode, though for a different reason.

6) It is customary for heroes to deliver a crie de guerre or similar before laying the smack down on the villains. These characters recite a prayer before dispensing justice, one which is not followed by the usual "amen."

I really don't have a clue and I can't find anything that comes close.