I'm doing something similar with FRUA and Ultima VI. But I'm also targeting Falcon/TT first, then going to try and get them running on an ST.
The reduction to only requiring 4mb of ram seems pretty required, since normal hardware is kind of maxed out at that (without adding in something like a pistorm, etc).
Still, it's hard to believe you got that to run even in Hatari in ST mode, plus with that good of sound! Insane what the AI can do these days...