To answer your question about the licenses is a little involved.
The whole system is comprised of a front end language (SOUL), an intermediate representation (Heart) and a runtime to JIT the code (no clever name for this, we call it a SOUL runtime). The runtime takes in Heart, not SOUL, and JITs this, or, we can convert this to C++ as well for integration into more conventional projects.
As of now, the open source bit is the parser and compiler which converts SOUL into Heart, so basically the language definitions are open source as well. We haven’t opened up the runtime, and this is for a number of reasons, from boring things like we’re not sure if we’re going to license this code to device manufacturers or open it, through other things like there’s lots of churn in that part of the code, and we’re still working through what we want the interfaces to look like.
I’m guessing from your comment that you don’t want to commit to something which requires closed source components, and I totally understand that. We might see some movement in this direction soon, with either this implementation being opened up, or a reference implementation being released.
Meanwhile, the closed source binaries have been released with very permissive licenses - you can use them for fun or in commercial products.