Ok, short update:
Managed to get past the "stinking knave..."-freeze in Valkyrie Profile by turning off the frame limiter (!). Weird thing is I get about 100 - 200 fps without the frame limiter and no hiccups whatsoever. The game runs way too fast, of course, but doesn't this mean that somethings wonky with the frame limiter on a Galaxy S3? Without frame limiter = overkill fps, with frame limiter = continuous dips into the 30 - 40 fps area.
Also, the three games I've put the most time into, FF8 and Valkyrie Profile now all go from perfect 60 fps to a gradual decrease in fps over a duration of say 15 - 20 minutes. After a while they all pan out at about 40ish, albeit unstable, fps. If I quit and restart I go from 40ish to rock solid 60 fps again in the same area in Valkyrie Profile and FF8. This is all in software mode. I guess I could stand the 40 fps if it was stable and thus didn't make the soundtrack go bananas along with it. (edit: turning Hardware Acc. off / on resets this for a short while).
I've fiddled around with every imaginable setting in Open GL and it's pretty much still unplayable no matter the game (Parasite Eve 1 / 2, FF Tactics, FF8 - known issue, Persona 2, Valkyrie Profile, Castlevania : SOTN). I don't care much for Open GL though, I just wanna play the games. If I got software mode to work correctly I'd be happy as a clam.
Is the developer reading on the forums by the way?