In the musical blues sequence, Cliff (BB Hooker) appears to be playing a Gibson ES-335, but the Gibson logo has been taped over probably because it would be cost a fortune to use the Gibson name.
Olivia lip-synchs Koko Taylor's "I'm a Woman". This was similar to what the family did for Cliff's parents anniversaries in seasons two and three. In S2E3 the family performed Ray Charles "Night Time Is the Right Time", with Theo, Rudy, and Cliff each lip-synching a solo. And in S3E3 the family performs James Brown's "I got the Feelin'".