No, they are never seen even in informal writing.
The only time they might show up in writing is between quotation marks, to quote exactly a speaker with a highly idiosyncratic way of speaking.
"In-totally-credible" is the one heard most often, I think. I think there was a character on the TV comedy show Saturday Night Live who used that phrase, and maybe "fantabulous."
I have never heard the ones you cite, except for "fantabulous."
This is a kind of slang that became overused so rapidly that it lost its charm -- which was only ever "moderate" in the first place. I think it was always too self-conscious and labored to sound like real slang.
Sometimes an expletive is inserted inside another word. For example, the locution "In-f***ing-credible!" might still be heard under the right (limited) circumstances.
There was a failed journalistic effort by Time Magazine (in the 1930's I think) to condense words in this manner. This highly-stylized writing style was the subject of much ridicule and parody. I tried to find some examples on line, but I couldn't. "Boatycoon" to describe a shipping magnate (boat tycoon) might be an example.