A couple of observations:
1. You can always split open / cut back the black plastic sheath on the pickup lead to expose more of the inner wires if you need to.
2. Splicing wires is easiest done by twisting the wires together, soldering the twisted ends using just enough solder, then folding the ends over and putting heat shrink over the joint.
3. On those CTS push-pulls, I like to pre-tin the wire ends, then push them through from behind, then use just enough additional solder to fix them. This helps prevent too much solder creating "shorts" on the faceplate, keep things looking neat, and helps prevent charging or melting of the insulation.
4. The split humbucker wires go black (hot) to the lug on the pot part of the push-pull, not to the push-pull; red and white get joined together and both go to the same C1 or C2 on the push-pull; green and bare get grounded to the pot casing. You run another wire from the selected push-pull contact to ground on the same pot casing.
5. Even coil split, the "tap test" (tapping the poles with a screwdriver or something), often produces some sound that you think is coming from the deactivated pickup. You're giving the pole pieces a comparative mighty whack and thus still disturbing the overall magnetic field and inducing some current in the active pickup.
6. The maxim "the bigger the blob, the better the job" is a joke. Use just enough solder to get a joint.
7. Test each joint with a multimeter as you go.