Continuity mistake: In the flashbacks to 1984, Peter and Lois are both 18, but in a previous episode, Lois says that she's two years younger than Peter.
Continuity mistake: When Peter goes back in time the first time, we see him and Cleveland slapping hands around the pool, we see that the pool is significantly shorter than in the scene where we first see Lois.
Other mistake: Peter goes back in time and sees Lois at age 18. Death says everyone will see Peter as being 18 too. Problem: Lois and Peter aren't the same age. In later episodes, Lois reveals she's 2 years older than Peter so Peter should be 16 when he meets Lois.
Factual error: When Peter is sent back to 1984, he plans to see Zapped! in the theater with Lois; Zapped! was released in 1982, and was no longer in theaters by 1984.
Chosen answer: It's a real song called "Elvira". Originally by Dallas Fraizer in '66, however, this version seems to be the Oak Ridge Boys cover version. However, the mega lesbians skip the verse and just sing the chorus after the opening line.
Bishop73