It's a stretch to say this is the end of legacy Six Flags IP. Peanuts Worldwide appeared on just about every legacy Cedar Fair URL.
And from the very first press release from Six Flags Entertainment Corporation:
"ABOUT SIX FLAGS ENTERTAINMENT CORPORATION
Six Flags Entertainment Corporation (NYSE: FUN) is North America’s largest regional amusement-resort operator with 27 amusement parks, 15 water parks and nine resort properties across 17 states in the U.S., Canada and Mexico. Focused on its purpose of making people happy, Six Flags provides fun, immersive and memorable experiences to millions of guests every year with world-class coasters, themed rides, thrilling water parks, resorts and a portfolio of beloved intellectual property such as Looney Tunes®, DC Comics® and PEANUTS®." (emphasis mine).
Six Flags Entertainment Corporation - Cedar Fair and Six Flags Merger of Equals Successfully Completed, Creating a Leading Amusement Park Operator