The intended solution uses all of the skills, including the pickup. Changing the release rate is not necessary, but can help during at least one of the steps.
Deception is a key theme of this puzzle. Keep in mind the level's rule. Although it looks like each group is separate, it's necessary for them to help each other.
Although each goal can only accept 10 lemmings, keep in mind that it doesn't have to be the 10 from the hatch in the same quadrant as the goal. All 10 lemmings from one hatch don't necessarily need to go to the same one goal, either.
Careful observation of the terrain helps a lot in this level. The positions of many of the objects and slopes are deliberate, as are the holes.
View the pickup as a hint for where a lemming needs to go, rather than as an obstacle. What can a lemming do from in there?
Don't forget that bashers can remove floors and diggers can remove walls. It may even be possible to do both at once.
Sometimes, even the smallest of gaps require a platformer to cross. Sometimes, it's better not to cross large gaps at all.
Figuring out where to use the climber is important. Which quadrant benefits most from a climber? What impact does that have on the solution as a whole? What can a climber do in the later stages of the puzzle that no other lemming can?
Most of the top-left crowd is contained. They are the last group to have the path prepared for them, and are thus the last lemmings to exit the level.
The pickup is not collected by a lemming from the top-right hatch. Consequently, a lemming from a different quadrant must enter this quadrant.
A digger is not used in the bottom-left quadrant. The goal is reached via a different method, thanks to some outside help...
All 10 of the lemmings from the bottom-right hatch exit via the bottom-right goal. They still use some outside help to get there, though...