[Newbies] Q: Standard Lisps on the Squeak VM?

For a variety of reasons, I have a hunch that a Lisp would be a useful language for building Croquet worlds.

So, I browsed the Squeak Map and saw several Lisp implementations for Squeak.

While I appreciate that most of them are proof-of-concept experiments, one of them may prove useful for practical programming. If you have already looked at any of these Lisps, you may be able to help me choose which to investigate more deeply: Which of the Squeak Lisps came closest to implementing a standard Lisp (either R5RS Scheme or ANSI Common Lisp)?

I have some extra questions as a postscript.