NIFTI files are almost inherently de-identified as most of the tags in the NIFTI files do not contain PII. You could try just converting them to NIFTI and then check the headers using 3dinfo or nifti_tool to check to make sure nothing slips in the NIFTI file that you're worried about. If this works, you could skip the anonymize dicom step.

A growing number of sites are recommending that you remove the face on the structural T1 images. There are a variety of ways of doing this, but some of them cause issues for further processing (e.g. freesurfer). In an ideal world, I'd recommend using pydeface or a full skull strip (3dSkullStrip or @SSwarper).

If you're feeling kind, it would also be nice to run the basic Freesurfer pipeline (recon-all -autorecon1) removing the T1.mgz and orig.mgz files and then sharing the rest of the Freesurfer output directory.