I was under the impression that hex editing entailed changing values and that assembly hacking entailed having to actually write code.
And I was wondering whether I'd have to write the code itself.
In the end, assembly code is just hexidecimal reformatted to look a little more readable. And in the end, if you have to write new assembly code, you'll still have to find some way to edit the existing code so that the program will know to use your new assembly code.
Would I be correct in assuming that I'll have to find a program that'll let me debug the game so that I'll be able to see what's going on and using a hex editor to change it from there?
Yes, you'll need some way to debug the game. But this might be easier than it sounds. This is why I was referring to NTR cheat plugins.
See, way back in the days of 16-bit consoles, it was often easy to use a device like an Action Replay to, for instance, let you have unlimited lives in a game. If you started with 5 lives, then you could start the game, and search the console's RAM for every instance of the value "5". Then you could lose a life, and look at which of those instances changed to "4". And so on, and eventually you'd find the spot in the console's RAM where the current number of lives is stored, and then you could use the Action Replay to keep that value set at 5 at all times, and presto – unlimited lives.
Notice that I'm saying "RAM". In a case like this, the console loads the value of 5 from somewhere in the game's ROM when the game starts up, but we don't have to know anything about how it does that, or how the game's program decides to reduce your number of lives, or anything else like that.
So, I'm guessing
you can use an NTR cheat plugin on a 3DS in a similar way to find the coordinates of the camera, and then manipulate those coordinates as you see fit – without having to make any changes to the ROM or extensively analyze the game's code. Lots of people seem to be writing NTR cheat plugins these days, which would seem to indicate that it's not especially difficult. That said, I've never done anything with NTR cheat plugins myself.