How to musically bridge gap between different musical pieces

I’m replacing audio in a project because of licensing issues. It is a stage production with 4 different songs, some fade and some have hard endings. There is silence between the songs and my goal is to make it a 20 minute “score” instead of 4 separate pieces of music. The catch is that the beats/tempo must be the same as the original music as it is a live dance show. My question is, technically, how to deal with those gaps in the audio.

I plan on using C6 to make a tempo map of the entire work, but then how to tackle the gaps? My ideas so far:

  1. Add bars to the previous piece and see where there is a downbeat. With any luck, it will be close to the next song’s beat and I can change the tempo of the bars in the gap some.

  2. If a fade, I can just bounce the last few bars of the song and repeat and fade (since I cannot have multiple tempos at the same time).

  3. Use “process bars” to create some sort of ritard/accelerando into the next piece. ANY ADVICE ON HOW TO DO THIS WITHOUT CHANGING THE DOWNBEAT/TEMPO OF THE NEXT SONG WOULD BE GREAT!

  4. Having a chord or sound that holds over (fermata) until the next song begins, thereby obscuring any odd bar/tempo changes that might exist in the gap.