Your idea sounds pretty good, but as muttdoggy has said, you are going to require permission to make a 3D remake, but there is a solution to that problem, instead of making a remake about that game, create a new game set in that world , (something like a spin-off using another character) would technically be a new game, you don't need to add the npc, and you can add the locations that exist in that world without the creators bothering.
the only thing is that I suggest that you try to be as faithful to the original theme, don't turn Tel'Adre into a futuristic city or something like that.
otherwise, if you are going to create a 3D game I suggest you do it in unity, there are several video game engines, but unity is quite comfortable.
Finally and most importantly, pay attention to properly adapt the mechanics of the original game to your 3D game, that is to me the greatest difficulty, for example there is the fact of the sand witch, she has 2 pairs of tits, she thinks that Most of the 3D libraries that use humanoid characters do not have similar characters, likewise the transformations of a character that can become an anthropomorphic fox, cat, and even spider or dragon, for example, it will be a real challenge , you become experimenting with the mechanics of the game to see how possible your project is.