Haven't used RPGM myself, but the decryption works fine. You should be able to load the game into RPGM without problem. No idea what other tools or extensions the devs use, but it should at least work without them just fine.
Problem is that many game mechanics are stored in new internal values. From these your ingame stats are constantly updated. No idea what save edit gives you access to all internal values, but my advice would be to edit the js files where the values are calculated (for an idea see link in OP).
Code fragments suggest the idea of smegma as a game mechanic. It's been there for quite some time and while I personally hope it gets dropped this may be a feature in future releases. If that happens, there'll be a fast tweak to disable it for sure