Glad you're giving RPG Maker a chance. I think it's perfectly fine engine, depending on what you want to make of course.
Sure you can look at F&H's coding, but it's a severe case of spaghetti coding. I feel sorry for anyone who ever tried to make sense of it. Again, you can do that if you want, but I'd recommend getting familiar with the engine otherwise and creating your game from scratch. Maybe look at F&H's eventing and coding for reference, but otherwise stick to your own project. But ultimately it's your choice.
You can use textures as a base. I don't mind seeing edits and such around in finished projects either, just as long as your game doesn't rely 100% on F&H graphics.
Good luck with your project!