Cute 9 seems to work fine for me. saved 20 lemmings.

I love the YIPEE! sound when entering home. But I also get sick of hearing it so much I changed it to BOING!
It might be pleasant to mix the two... only yell yippee on first or last lemming? Or every 3rd one yells Yippee?
Or always do the "Boing" in ffwd mode?

I think three sound samples that have a random-fire method would be lifelike and not as robotic as a perfect 1-2-3 system.
A boing, a swoosh, and a yippee.

I attached the third swoosh sound I had in mind.

*Edit: I edited the WAV file and added a shortened version now.

Here's my notes on updating all four waters:
However, I updated the pack you're playing (World Tour) using the above method and there are a handful of levels that did not update.
Most did however. I love rock and roll, we're not going to take it, and more needed manually fixed. No idea why.
Here's the basic info...

Search and replace text:

STYLE orig_fire\r\n   PIECE water
to
STYLE orig_fire\r\n   PIECE lava

STYLE orig_marble\r\n   PIECE water
to
STYLE orig_marble\r\n   PIECE poison


STYLE ohno_bubble\r\n   PIECE water
to
STYLE ohno_bubble\r\n   PIECE blasticine

STYLE ohno_rock\r\n   PIECE water
to
STYLE ohno_rock\r\n   PIECE vinewater

That sounds good.
I'd personally be plenty happy with a simple version that adds a check-box to settings like (Faster FFWD Speed)
or something.
But fancier is okay too.

Here's a Logo file I made for this pack. I've made logos for every pack in my computer that was missing them. (That's how serious my life is lately)

Yes, I got the Milla graphics working.

To be more specific to this issue, though, we have an opportunity here to tidy things up like the menu graphics, UI layout, etc. If that means a few signs need to be updated to match the changes, I'd say it's a worthwhile trade-off

I think I've downloaded every level pack. I'm willing to update every sign to the new SLX standard if there's some way to make them available.