Talking about fit with the ecosystem; I couldn't find any documentation on:

a) how interop with Java is handled b) what kind of performance we'd be getting

Based on what I've seen so far Redline could just as we'll be a naive Smalltalk VM written in Java.

Clojure does it fairly well showing off interop with a few lines of idiomatic code and addressing performance by showing how close to the metal you can get with type hints and having the garbage collection tweaks ready to go.