The circuit for this project is straight-forward. The two servos are connected to the Circuit Playground Express, via pads A1 and A2.
You could use alligator clips to connect to the pads, or M3 nuts and bolts. The problem with both those is that they add more weight!
Just as with a planetary probe descent system, every bit of extra weight must be compensated for by the descent system. With this in mind, the connections to the servos can be made with the jumper wires (that plug into the servo cable's connector) soldered directly to the pads.
You can use a desoldering braid later to remove the solder and use your Circuit Playground Express with clips or a CRICKIT again.
You can take weight reduction to an extreme if you like (and go for the full JPL experience): trimming and soldering the wires from the battery and servos directly to the pads in an attempt to shed the weight of the extra wire and connectors. That's getting a bit excessive, though. Especially if you want to use the parts for other projects in the future.