This last one is particularly interesting. Redline compiles to the exact same bytecode as any JVM language (eg, Java, Scala, Groovy, Clojure, etc.). It is also optimized to use dynamic dispatch, JIT, etc. Redline classes are compiled to bytecode in exactly the same format as Java classes, so integrating the two is seamless. In fact, you can import Java classes and treat them like Smalltalk classes, even adding new methods at runtime.
A Redline plugin is available for IntelliJ IDEA that provides similar debugging capability as in Smalltalk IDE.
Redline is about removing the barriers that people see with Smalltalk, namely IDE, lack of command line and file-based items. While these may be just the things that make Smalltalk more productive, they need to be slowly introduced once people are onboard with Smalltalk. This is the approach Redline is taking.