if you assign climber to the 1st lemming right at the start of the level, then you can let it cycle in the button area to wait for the correct opportunity to set the blocker. Then it is easier to work on the distance between 1st and last lemming.

Bonus 1 : Hardest level of the pack for me, what a tough one to start the rank. I must say I cheated a little for this one, because while trying to solve the previous issue I had on Bonus 6, I saw a screenshot of a video by Swerdis which shows the position of the first blocker in this bonus 1. I did not think at all to set this blocker here, and it lead me to the solution.
It is another case of "assign the skill that will free the blocker before the blocker is even set", always hard to see for me.
Also my solution does not use the two upper pickups. For a long time I tried to catch them, but ended one lemming short of requirement, and this was because getting the two upper pickups used 1 climber and 1 builder, made me gain 1 climber and 1 builder, but loose the lemming ! So yeah, do not get those pickups and you're done. Intended ?

Bonus 2 : Better love sliders to play this one ! I could make a structure at the beginning to sort the swimmers and sliders directly, and another structure at the end to make them all go to their respective exit.
In the end I think my solution is quite clean, and I have one stacker and a couple of shimmier left. Maybe this was not intended ?

Bonus 3 : I could clear it with almost extensive study of all the possibilities here. Just save destructive at all cost.

Bonus 4 : Once you realize you only need 1 swimmer to cover the whole water needs, the level becomes easier ! Typical Armani stuff with the new skills : cloner a constructive lem, make a stoner at the most improbable place, have fun with gliders.

Bonus 5 : Easiest of the Bonus rank, may have been in the previous ones. At first I could not solve it because I was a bit frustrated by the others before and was searching for complicated stuff. This is a very regular level with a nice touch : assign the climber at the correct time.

Bonus 6 : Weirdly enough, this was a quick clear for me after the "hatch above the water??" issue was resolved by kaywhyn some posts earlier. The use of the cloner and builder is quite clear, getting a glider to shimmy all the way up is a bit tricky but nothing undoable if you've played some Armani before. Weircly enough, the hardest part for me was to time the fencer correctly so that the crowd would stay compact and go to the exit quickly enough.
But then saving the last glider was the thing : when you're out of everything, and playing the last level of a pack, what should you do ? I could find this fast enough because I had nothing else to do, and also because I recently played a kaywhyn's level in contest 33 that uses about the same trick : neutralize a lem for some frames with a oh-no animation.