My opinion here; Despite other people complaining about it being a blitz3D wrapper- my view here is that although you are on the edge, you are not providing the compiler itself. I myself did a little project like this a couple of years back called Cygnus Novascript- there were no issues with it at all. If you were to be providing the Blitz compiler, that would be an issue.
You WILL need to purchase a Blitz3D license in order to continue with this.
Note that I am not BRL though, just a long term member. The final say will come from Mark Sibly.
Blitz3D SDK is just the Blitz engine in a DLL for use in C++/C# etc.