For more questions regarding usage, feel free to contact the artist directly.
Your license CC BY-NC-ND doesn't allow for any sort of reuse. I would suggest you change it to CC BY-NC, so that people searching for non-commercial usable materials will actually be able to find it. Definitely make sure you keep the -NC though if you don't want people using it for commercial purposes. Ideally, you'd speak with an attorney licensed to practice in Pennsylvania. IANAL.