Judy works at C.J. Neppey's, which is a spoonerism of J.C. Penney's.
The song "Sidney" sings after seeing his garden destroyed is "The Lord is Good To Me" from Disney's animated version of 'Johnny Appleseed.' Both Disney and Johnny Appleseed were referenced earlier in the episode.
Roger is whistling the National Anthem of Germany in the store while he doodles on the magazine. It also seems like the lady who bought Stan's Celebeartions now owns this store instead of the one she bad.