I don't know much about ROM hacking, but there sounds like way too much room for error in recreating the behaviours and physics of all the sprites. >_< While you may be able to recreate how Link recoils from an enemy blow or how he reappears after falling in deep water (that he can't swim in yet) or lava or a pit, enemy behaviour is yet another story...
Then again since I know little of hacking, or recreating behavious on sight alone, how can I really say? I just figure that once the structure of the ROM is figured out, there would be 100% accurate physics, behaviours, effects, palette limitations, etc. and all one would have to do is arrange the landscape/dungeon tiles accordingly. Even more so considering that I made little that was actually custom.
Though I suppose that what is custom might be hard to add in. In any case, good luck with the Spinner and the Spinner tracks. You'll have to get the physics just right for the puzzles to work out as I intended...
And now you can see why I'm hesitant about this whole thing, even after giving permission. I always feel like every deviation/addition would not be how I imagined it, that I would rather that the maps not be used exactly as they are. Though as long as it's clear that the fan game is BASED on my maps, and that everyone knows the maps came first, I'm as OK with it as I'll ever be.