I'm thinking the CM was informing you incorrectly.
I just made some major changes to my schedule (8/14-21) a couple days ago and had NO problems with getting a Coral Reef lunch, Prime Time Cafe dinner, Ragland Road dinner, and Teppan Edo dinner. I asked about GF Cafe and was given a list of at least 8 times between 5 and 6:30 for dinner. The only ones that I was told had NO availability were Chef Mickey, LeCellier, and 'Ohana.
There are still reservations to be had. You'll have to be flexible, but there are still openings.