Is it possible to run fmri- or smriprep if subjects have only whole-brain T2 data?

Summary of what happened:

One of our collaborators would like us to process an fMRI dataset; however, only whole-brain T2w anatomical data is available.

I was wondering: is it possible to instruct fmriprep to use T2w data for co-registration? (I understand freesurfer is out of the question for this dataset)

Version:

fmriprep version 21.0.1

Environment (Docker, Singularity, custom installation):

singularity 3.4+

Not to my knowledge. sMRIPrep requires a T1 image, and fMRIPrep uses sMRIPrep.

I guess I could do the T2-coregistration and fmriprep analysis separately (with the understanding that I would be forfeiting some features).

If so, would you recommend I do the T2 ← BOLD co-registration before or after fmriprep processing? (I assume I should also include MNI152 normalization in this step too?

How will you do fMRIPrep processing at all without a T1?