I think the key info here is the length of new sound wall at 1,730 feet and the addition of six new light poles. Based on the satellite image and spacing of existing light poles, and the length of the wall, that doesn't appear to be enough to use the southeast corner and southern sections. But six new light poles and 1,700 feet of wall would be perfect for the narrow strip of dirt along the eastern side of what is now CM parking attached to the Katella CM parking lot, behind the apartments on Haster Street.
This appears to be expansion of the CM parking lot, not the Toy Story lot for paying visitors, although it's technically the Toy Story lot because it's also accessible via Harbor Blvd. and an access road from the Buzz Lightyear section of the lot.