What songs do the orange plum dark blue and gold sing-a-ma-jigs duets sing?

There are only 3 sing-a-ma-jigs, Plum, Orange and Blue (no dark blue or gold). Here are their duets:

1. Hey You!

- Blue and Orange

2. Fruit Friends

- Orange and Plum

3. Best Buds

- Plum and Blue

4. Happy Times

- Orange, Plum, and Blue (trio)