The phrase "affable character" is correct and usable in written English.
It can be used to describe someone who is friendly, pleasant, and easy to talk to, often in a context discussing personality traits.
Example: "Her affable character made her the perfect host for the dinner party, as everyone felt at ease in her presence."
Alternatives: "friendly disposition" or "pleasant nature".
Said to be an affable character, this dance-like music smiles right through.
Instead, Mr. Skilling showed himself to be a vulnerable, emotional, even affable character.
He is an affable character, who likes to laugh and joke with the press, and who feigns tactical naivety.
Instead, Skilling showed himself to be a vulnerable, emotional, even affable character who saves his hostility, these days, for the government that charged him with defrauding Enron's investors.
Though often derided for his dour demeanour, Merrick is actually quite the joker, and an affable character to boot.
Russell, 57, is an unhurried and affable character who says he enjoys walking the factory and getting feedback.
This first episode of this new series, Educating Yorkshire, which follows on from Channel 4's successful Educating Essex, focused on a handful of affable characters at the Thornhill Community Academy in West Yorkshire.
At the height of the black-power movement, when his articulate, educated and even affable characters were often measured against fiery political icons such as Malcolm X and the Black Panther leader H. Rap Brown, some blacks felt ambivalent about Poitier.
Mr. Morgan's Sprinkles may carry a gun, but he is a spinoff of his affable comic character on "30 Rock".
In another scene, Eddie's teacher can't pronounce his Chinese name so the affable main character replies, "Just call me Eddie".
To answer your first question: No, Colbert was not in character, as evidenced by the stylish black glasses he wore, rather than the conservative wire-rim frames his blustery character prefers and, of course, by his modest and affable persona.
