>>150929655
What they explained in Create Unknown was they had a budget for small cameos. They decided to leave talking to CWC for the very last, because they knew if they did it in advance, he'd go on social media and talk about it. When they decided it was time to talk to him, the network told them they were over the cameo budget and if they wanted to bring him in, he'd have to be in more than a couple lines for one role.
Zach and Mike thought it wouldn't be funny that way, that the joke being funny depended on it being literally just those two lines and nothing else, and instead asked Harry Partridge to do a CWC voice for Grease.

Then the Barb Revelation happened, and they realized the bullet they'd dodged, entirely by accident.