Turns out that this is probably far less interesting. With the current repo state, most of these manifest as java stack exception. About the most that I can "hang" the parser right now is 3-7 second at a time. (
i7@2.5Ghz, sun "jre 8") Not sure if that is a problem. Noticed heap GC got a little crazy though, so it might be that it could still be tuned into a combination problem.
java stack exception as in "maximum allowed AST depth reached?" or a true java stack exception?
In my eyes 7 seconds is bad enough

I will send you a BTC from my own savings soon, to express my gratitude for helping me with the parser.
We still have to figure out what to do with this awful FAA ;-) And, generally, with all those other "really interesting attacks".
And I hope that we will soon see official bounty bug hunting guidelines here, but until then I strongly assume that you will be rewarded by Lannister for sure

Thanks once again for all your help, without you we would be 10 steps behind.