I'm still not getting your use of "mascot." CBS wasn't bringing a guy in a Snoopy suit to all of its live event coverage or showing a slide of Charlie Brown before "The Mary Tyler Moore Show." Peanuts wasn't even a character, just the name of Charles Schulz's comic strip and licensing cash cow, so how could he/she/it be a mascot?
The typical mascot is exemplified by the San Diego Chicken....
https://en.wikipedia.org/wiki/San_Diego_Chicken
It's a cartoon character outfit worn by a station employee and used everywhere from remotes and sporting events to concerts and charity fund-raisers.
Some stations have had live mascots; I had a kangaroo (actually a wallaby) called "Kanga-Q" at 11-Q in San Juan in the 70's. But live animals are usually tedious, so the costumed wolf, pig, vulture or armadillo is what generally is used.
Generally, someone else's registered design is not used as a radio or TV station mascot. It's a proprietary design created for the station.
Of course, there is a difference between a symbol and a mascot. There were plenty of B's... from B 92 to B 107. They all had cute and cuddly bumblebee logos, but they did not carry a bunch of bees and hornets around to remotes. Same goes for "Tiger radio" and "the Wolf" and other names based on dangerous wild creatures. Those are not mascots, as the station does not have a tiger or a wolf in a cage at the studios. Again, symbols.
A mascot is, today, most often seen in college football games where the school symbol is an animal and there is someone wearing a costume representing that character that leads the crowd in cheers and the like.