I am trying to create a GitHub Pages site for an existing repo which already contains all the files that would belong in the assets/images and _data folders, i.e. hundreds of images and .json files. After adding a MySite Jekyll directory, I want my repo to look like this:

.
├── Images/
│   ├── imageFolder1
│   ├── imageFolder2
│   └── etc...
├── Data/
│   ├── data1.json
│   ├── data2.json
│   └── etc...
└── MySite/
    ├── _data/
    │   ├── <shortcut to data1.json here>
    │   └── <shortcut to data2.json here>
    └── assets/
        ├── images/
        │   ├── <shortcut to imageFolder1 here>
        │   └── <shortcut to imageFolder2 here>
        ├── css
        └── js

How can I make my image and json files accessible to Jekyll without having to duplicate them?

I tried using a symbolic link, both directly to the file and to the parent directory, but neither worked, despite disabling safe mode in configuration settings.