Any figures you create with MRIcroGL, Surfice and NiiVue are your own original art, and you do not need any permission to publish these: you and your co-authors are the original copyright holders.

While not required, I would be grateful if you could cite my tools. The current best citation is very old, and I need to stop developing new tools and publish a modern description. The best citation is:

Spatial normalization of brain images with focal lesions using cost function masking.